Files
nexus/sreweekly/articles/424/08-slo.html
2026-09-12 17:23:01 +08:00

490 lines
191 KiB
HTML
Raw Permalink Blame History

This file contains invisible Unicode characters
This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.
This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.
<!DOCTYPE html>
<html lang="en" dir="ltr">
<head>
<meta charset="utf-8" />
<meta name="norton-safeweb-site-verification" content="24usqpep0ejc5w6hod3dulxwciwp0djs6c6ufp96av3t4whuxovj72wfkdjxu82yacb7430qjm8adbd5ezlt4592dq4zrvadcn9j9n-0btgdzpiojfzno16-fnsnu7xd" />
<link rel="preconnect" href="https://substackcdn.com" />
<title data-rh="true">SLO - Alex Ewerlöf Notes</title>
<meta data-rh="true" name="theme-color" content="#001426"/><meta data-rh="true" property="og:type" content="article"/><meta data-rh="true" property="og:title" content="SLO"/><meta data-rh="true" name="twitter:title" content="SLO"/><meta data-rh="true" name="description" content="Dive into the fundamentals of Service Level Objectives (SLOs) with this guide. Understand SLOs, error budgets, and their practical implications through real-world examples. Learn to set and manage SLOs effectively with case studies on API service reliability."/><meta data-rh="true" property="og:description" content="Introduction to Service Level Objectives and their relationship with error budgets"/><meta data-rh="true" name="twitter:description" content="Introduction to Service Level Objectives and their relationship with error budgets"/><meta data-rh="true" property="og:image" content="https://substackcdn.com/image/fetch/$s_!xH-H!,w_1200,h_675,c_fill,f_jpg,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F0ec62079-bcea-47fa-aafc-e3f7b6ed0f9a_1054x876.png"/><meta data-rh="true" name="twitter:image" content="https://substackcdn.com/image/fetch/$s_!o1ez!,f_auto,q_auto:best,fl_progressive:steep/https%3A%2F%2Falexewerlof.substack.com%2Fapi%2Fv1%2Fpost_preview%2F142248697%2Ftwitter.jpg%3Fversion%3D4"/><meta data-rh="true" name="twitter:card" content="summary_large_image"/><meta data-rh="true" property="article:modified_time" content="2025-06-19T12:41:10.515Z"/>
<style>
@layer legacy, pencraftReset, pencraft;
</style>
<link rel="preload" as="style" href="https://substackcdn.com/bundle/theme/main.06a4c4c291d4583811c7.css" />
<link rel="preload" as="font" href="https://fonts.gstatic.com/s/merriweather/v33/u-4D0qyriQwlOrhSvowK_l5UcA6zuSYEqOzpPe3HOZJ5eX1WtLaQwmYiScCmDxhtNOKl8yDr3icaFF31CPDaYKfF.woff2" crossorigin />
<link rel="stylesheet" type="text/css" href="https://substackcdn.com/bundle/static/css/11100.cee9fbee.css" />
<link rel="stylesheet" type="text/css" href="https://substackcdn.com/bundle/static/css/86118.c25b9f67.css" />
<link rel="stylesheet" type="text/css" href="https://substackcdn.com/bundle/static/css/93519.6640a5b2.css" />
<link rel="stylesheet" type="text/css" href="https://substackcdn.com/bundle/static/css/42118.cba90b72.css" />
<link rel="stylesheet" type="text/css" href="https://substackcdn.com/bundle/static/css/39522.25128f14.css" />
<link rel="stylesheet" type="text/css" href="https://substackcdn.com/bundle/static/css/47358.668d8a3c.css" />
<link rel="stylesheet" type="text/css" href="https://substackcdn.com/bundle/static/css/94881.cb76fe04.css" />
<link rel="stylesheet" type="text/css" href="https://substackcdn.com/bundle/static/css/27386.72f00430.css" />
<link rel="stylesheet" type="text/css" href="https://substackcdn.com/bundle/static/css/76768.f15fc605.css" />
<link rel="stylesheet" type="text/css" href="https://substackcdn.com/bundle/static/css/41932.97d2663c.css" />
<link rel="stylesheet" type="text/css" href="https://substackcdn.com/bundle/static/css/48409.0588981c.css" />
<link rel="stylesheet" type="text/css" href="https://substackcdn.com/bundle/static/css/32552.313415d5.css" />
<link rel="stylesheet" type="text/css" href="https://substackcdn.com/bundle/static/css/27313.92c631cb.css" />
<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=0, viewport-fit=cover" />
<meta name="author" content="Alex Ewerlöf" />
<meta property="og:url" content="https://blog.alexewerlof.com/p/slo" />
<link rel="canonical" href="https://blog.alexewerlof.com/p/slo" />
<meta name="google-site-verification" content="HIy4u2xUDZkIs6P0KJw9TSYeq7KqXSPAQvZIs9911qU" />
<link rel="shortcut icon" href="https://substackcdn.com/image/fetch/$s_!j4nj!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Ffavicon.ico">
<link rel="icon" type="image/png" sizes="16x16" href="https://substackcdn.com/image/fetch/$s_!VSMg!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Ffavicon-16x16.png">
<link rel="icon" type="image/png" sizes="32x32" href="https://substackcdn.com/image/fetch/$s_!CJdc!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Ffavicon-32x32.png">
<link rel="icon" type="image/png" sizes="48x48" href="https://substackcdn.com/image/fetch/$s_!5Qve!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Ffavicon-48x48.png">
<link rel="apple-touch-icon" sizes="57x57" href="https://substackcdn.com/image/fetch/$s_!gV2k!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Fapple-touch-icon-57x57.png">
<link rel="apple-touch-icon" sizes="60x60" href="https://substackcdn.com/image/fetch/$s_!L4Uu!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Fapple-touch-icon-60x60.png">
<link rel="apple-touch-icon" sizes="72x72" href="https://substackcdn.com/image/fetch/$s_!X3nD!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Fapple-touch-icon-72x72.png">
<link rel="apple-touch-icon" sizes="76x76" href="https://substackcdn.com/image/fetch/$s_!Xe9B!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Fapple-touch-icon-76x76.png">
<link rel="apple-touch-icon" sizes="114x114" href="https://substackcdn.com/image/fetch/$s_!ef9e!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Fapple-touch-icon-114x114.png">
<link rel="apple-touch-icon" sizes="120x120" href="https://substackcdn.com/image/fetch/$s_!B-Gw!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Fapple-touch-icon-120x120.png">
<link rel="apple-touch-icon" sizes="144x144" href="https://substackcdn.com/image/fetch/$s_!PA8p!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Fapple-touch-icon-144x144.png">
<link rel="apple-touch-icon" sizes="152x152" href="https://substackcdn.com/image/fetch/$s_!x3Pg!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Fapple-touch-icon-152x152.png">
<link rel="apple-touch-icon" sizes="167x167" href="https://substackcdn.com/image/fetch/$s_!7ISu!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Fapple-touch-icon-167x167.png">
<link rel="apple-touch-icon" sizes="180x180" href="https://substackcdn.com/image/fetch/$s_!k1Y3!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Fapple-touch-icon-180x180.png">
<link rel="apple-touch-icon" sizes="1024x1024" href="https://substackcdn.com/image/fetch/$s_!hatU!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Fapple-touch-icon-1024x1024.png">
<link rel="alternate" type="application/rss+xml" href="/feed?sectionId=67723" title="Alex Ewerlöf Notes"/>
<style>
@font-face{font-family:'Merriweather';font-style:italic;font-weight:400;font-display:fallback;src:url(https://fonts.gstatic.com/s/merriweather/v33/u-4B0qyriQwlOrhSvowK_l5-eTxCVx0ZbwLvKH2Gk9hLmp0v5yA-xXPqCzLvPee1XYk_XSf-FmTCUG36AvH4ZL_Ean2DTA.woff2) format('woff2');unicode-range:U+0460-052F,U+1C80-1C8A,U+20B4,U+2DE0-2DFF,U+A640-A69F,U+FE2E-FE2F}@font-face{font-family:'Merriweather';font-style:italic;font-weight:400;font-display:fallback;src:url(https://fonts.gstatic.com/s/merriweather/v33/u-4B0qyriQwlOrhSvowK_l5-eTxCVx0ZbwLvKH2Gk9hLmp0v5yA-xXPqCzLvPee1XYk_XSf-FmTCUG3zAvH4ZL_Ean2DTA.woff2) format('woff2');unicode-range:U+0301,U+0400-045F,U+0490-0491,U+04B0-04B1,U+2116}@font-face{font-family:'Merriweather';font-style:italic;font-weight:400;font-display:fallback;src:url(https://fonts.gstatic.com/s/merriweather/v33/u-4B0qyriQwlOrhSvowK_l5-eTxCVx0ZbwLvKH2Gk9hLmp0v5yA-xXPqCzLvPee1XYk_XSf-FmTCUG34AvH4ZL_Ean2DTA.woff2) format('woff2');unicode-range:U+0102-0103,U+0110-0111,U+0128-0129,U+0168-0169,U+01A0-01A1,U+01AF-01B0,U+0300-0301,U+0303-0304,U+0308-0309,U+0323,U+0329,U+1EA0-1EF9,U+20AB}@font-face{font-family:'Merriweather';font-style:italic;font-weight:400;font-display:fallback;src:url(https://fonts.gstatic.com/s/merriweather/v33/u-4B0qyriQwlOrhSvowK_l5-eTxCVx0ZbwLvKH2Gk9hLmp0v5yA-xXPqCzLvPee1XYk_XSf-FmTCUG35AvH4ZL_Ean2DTA.woff2) format('woff2');unicode-range:U+0100-02BA,U+02BD-02C5,U+02C7-02CC,U+02CE-02D7,U+02DD-02FF,U+0304,U+0308,U+0329,U+1D00-1DBF,U+1E00-1E9F,U+1EF2-1EFF,U+2020,U+20A0-20AB,U+20AD-20C0,U+2113,U+2C60-2C7F,U+A720-A7FF}@font-face{font-family:'Merriweather';font-style:italic;font-weight:400;font-display:fallback;src:url(https://fonts.gstatic.com/s/merriweather/v33/u-4B0qyriQwlOrhSvowK_l5-eTxCVx0ZbwLvKH2Gk9hLmp0v5yA-xXPqCzLvPee1XYk_XSf-FmTCUG33AvH4ZL_Ean0.woff2) format('woff2');unicode-range:U+0000-00FF,U+0131,U+0152-0153,U+02BB-02BC,U+02C6,U+02DA,U+02DC,U+0304,U+0308,U+0329,U+2000-206F,U+20AC,U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD}@font-face{font-family:'Merriweather';font-style:normal;font-weight:400;font-display:fallback;src:url(https://fonts.gstatic.com/s/merriweather/v33/u-4D0qyriQwlOrhSvowK_l5UcA6zuSYEqOzpPe3HOZJ5eX1WtLaQwmYiScCmDxhtNOKl8yDr3icaGV31CPDaYKfFQn0.woff2) format('woff2');unicode-range:U+0460-052F,U+1C80-1C8A,U+20B4,U+2DE0-2DFF,U+A640-A69F,U+FE2E-FE2F}@font-face{font-family:'Merriweather';font-style:normal;font-weight:400;font-display:fallback;src:url(https://fonts.gstatic.com/s/merriweather/v33/u-4D0qyriQwlOrhSvowK_l5UcA6zuSYEqOzpPe3HOZJ5eX1WtLaQwmYiScCmDxhtNOKl8yDr3icaEF31CPDaYKfFQn0.woff2) format('woff2');unicode-range:U+0301,U+0400-045F,U+0490-0491,U+04B0-04B1,U+2116}@font-face{font-family:'Merriweather';font-style:normal;font-weight:400;font-display:fallback;src:url(https://fonts.gstatic.com/s/merriweather/v33/u-4D0qyriQwlOrhSvowK_l5UcA6zuSYEqOzpPe3HOZJ5eX1WtLaQwmYiScCmDxhtNOKl8yDr3icaG131CPDaYKfFQn0.woff2) format('woff2');unicode-range:U+0102-0103,U+0110-0111,U+0128-0129,U+0168-0169,U+01A0-01A1,U+01AF-01B0,U+0300-0301,U+0303-0304,U+0308-0309,U+0323,U+0329,U+1EA0-1EF9,U+20AB}@font-face{font-family:'Merriweather';font-style:normal;font-weight:400;font-display:fallback;src:url(https://fonts.gstatic.com/s/merriweather/v33/u-4D0qyriQwlOrhSvowK_l5UcA6zuSYEqOzpPe3HOZJ5eX1WtLaQwmYiScCmDxhtNOKl8yDr3icaGl31CPDaYKfFQn0.woff2) format('woff2');unicode-range:U+0100-02BA,U+02BD-02C5,U+02C7-02CC,U+02CE-02D7,U+02DD-02FF,U+0304,U+0308,U+0329,U+1D00-1DBF,U+1E00-1E9F,U+1EF2-1EFF,U+2020,U+20A0-20AB,U+20AD-20C0,U+2113,U+2C60-2C7F,U+A720-A7FF}@font-face{font-family:'Merriweather';font-style:normal;font-weight:400;font-display:fallback;src:url(https://fonts.gstatic.com/s/merriweather/v33/u-4D0qyriQwlOrhSvowK_l5UcA6zuSYEqOzpPe3HOZJ5eX1WtLaQwmYiScCmDxhtNOKl8yDr3icaFF31CPDaYKfF.woff2) format('woff2');unicode-range:U+0000-00FF,U+0131,U+0152-0153,U+02BB-02BC,U+02C6,U+02DA,U+02DC,U+0304,U+0308,U+0329,U+2000-206F,U+20AC,U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD}
</style>
<style data-pub-theme-prefix>:root{--color_theme_bg_pop:#FFBC52;--background_pop:#FFBC52;--color_theme_bg_web:#001426;--cover_bg_color:#001426;--cover_bg_color_secondary:#0f2233;--background_pop_darken:#ffb238;--print_on_pop:#ffffff;--color_theme_bg_pop_darken:#ffb238;--color_theme_print_on_pop:#ffffff;--color_theme_bg_pop_20:rgba(255, 188, 82, 0.2);--color_theme_bg_pop_30:rgba(255, 188, 82, 0.3);--print_pop:#ffbc52;--color_theme_accent:#ffbc52;--cover_print_primary:#ffffff;--cover_print_secondary:#d9d9d9;--cover_print_tertiary:#d9d9d9;--cover_border_color:#ffffff;--font_family_headings_preset:'SF Pro Display', -apple-system, system-ui, BlinkMacSystemFont, 'Inter', 'Segoe UI', Roboto, Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol';--font_weight_headings_preset:900;--font_family_body_preset:Merriweather,sans-serif;--font_weight_body_preset:400;--font_preset_heading:sans;--font_preset_body:fancy_serif;--home_hero:feature-media;--home_posts:custom;--home_show_top_posts:true;--web_bg_color:#001426;--background_contrast_1:#0f2233;--background_contrast_2:#223443;--background_contrast_3:#485663;--background_contrast_4:#6d7882;--background_contrast_5:#aeb5ba;--color_theme_bg_contrast_1:#0f2233;--color_theme_bg_contrast_2:#223443;--color_theme_bg_contrast_3:#485663;--color_theme_bg_contrast_4:#6d7882;--color_theme_bg_contrast_5:#aeb5ba;--color_theme_bg_elevated:#0f2233;--color_theme_bg_elevated_secondary:#223443;--color_theme_bg_elevated_tertiary:#485663;--color_theme_detail:#192b3c;--background_contrast_pop:rgba(255, 188, 82, 0.4);--color_theme_bg_contrast_pop:rgba(255, 188, 82, 0.4);--theme_bg_is_dark:1;--print_on_web_bg_color:hsl(208.4210526315789, 25.00000000000006%, 90.74509803921569%);--print_secondary_on_web_bg_color:#99a1a8;--footer_bg_color:#000C17;--footer_bg_color_h:208.69565217391306;--footer_bg_color_s:100%;--footer_bg_color_l:4.509803921568627%;--print_on_footer_bg_color:hsl(208.69565217391306, 25.000000000000057%, 90.45098039215686%);--print_secondary_on_footer_bg_color:#999ea2;--footer_bg_contrast_1:#0f1b25;--footer_bg_contrast_2:#222d36;--footer_bg_contrast_3:#485158;--footer_bg_contrast_4:#6d737a;--footer_bg_elevated:#0f1b25;--footer_bg_elevated_secondary:#222d36;--footer_bg_elevated_tertiary:#485158;--footer_detail_color:#19242e;--background_pop_rgb:255, 188, 82;--color_theme_bg_pop_rgb:255, 188, 82;--color_theme_accent_rgb:255, 188, 82;}</style>
<link rel="stylesheet" href="https://substackcdn.com/bundle/theme/main.06a4c4c291d4583811c7.css" />
<style data-pub-theme-postfix></style>
<script async="true" src="https://www.googletagmanager.com/gtag/js?id=G-G8RXW18CW7&l=GA4DataLayer" >
</script>
</head>
<body class="">
<div id="entry">
<div id="main" style="--post-preview-border-radius:var(--border-radius-xs);" class="main typography use-theme-bg"><div class="pencraft pc-display-contents pc-reset pubTheme-yiXxQA"><div data-testid="navbar" class="main-menu"><div class="mainMenuContent-DME8DR"><div style="position:relative;height:93px;" class="pencraft pc-display-flex pc-gap-12 pc-paddingLeft-20 pc-paddingRight-20 pc-paddingTop-0 pc-paddingBottom-0 pc-justifyContent-space-between pc-alignItems-center pc-reset border-bottom-detail-k1F6C4 topBar-pIF0J1"><div style="visibility:visible;flex:1 0 0;" class="logoContainer-p12gJb"><a href="/" native class="pencraft pc-display-contents pc-reset"><div draggable="false" class="pencraft pc-display-flex pc-position-relative pc-reset"><div style="width:40px;height:40px;" class="pencraft pc-display-flex pc-reset bg-white-ZBV5av pc-borderRadius-sm overflow-hidden-WdpwT6 sizing-border-box-DggLA4"><picture class="pencraft pc-display-contents pc-reset"><source type="image/webp" sizes="40px" srcset="https://substackcdn.com/image/fetch/$s_!_Ur2!,w_40,h_40,c_fill,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png 40w, https://substackcdn.com/image/fetch/$s_!_Ur2!,w_80,h_80,c_fill,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png 80w, https://substackcdn.com/image/fetch/$s_!_Ur2!,w_120,h_120,c_fill,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png 120w" style="display:none;"/><img style="object-fit:cover;width:40px;height:40px;" src="https://substackcdn.com/image/fetch/$s_!_Ur2!,w_40,h_40,c_fill,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png" srcset="https://substackcdn.com/image/fetch/$s_!_Ur2!,w_40,h_40,c_fill,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png 40w, https://substackcdn.com/image/fetch/$s_!_Ur2!,w_80,h_80,c_fill,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png 80w, https://substackcdn.com/image/fetch/$s_!_Ur2!,w_120,h_120,c_fill,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png 120w" sizes="40px" alt="Alex Ewerlöf Notes" draggable="false" class="pencraft pc-reset"/></picture></div></div></a></div><div style="flex-basis:0px;flex-grow:2;min-width:0px;display:flex;justify-content:center;" class="logoTopCenterSlot-hss6WZ"><div style="flex-grow:0;" class="titleContainer-DJYq5v overflowVisible-joA5t0"><h1 id="wordlogo" class="pencraft pc-reset font-pub-headings-FE5byy reset-IxiVJZ title-oOnUGd titleWithWordmark-GfqxEZ"><a href="/" class="pencraft pc-display-contents pc-reset"><img alt="Alex Ewerlöf Notes" src="https://substackcdn.com/image/fetch/$s_!3m6V!,e_trim:10:white/e_trim:10:transparent/h_84,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fbd56dc7c-4b9f-43f2-99a1-ecc995284940_1200x256.png" style="max-height:42px;" class="wordmark-WcDTTu"/></a></h1></div></div><div style="flex-basis:0px;flex-grow:1;min-width:fit-content;" class="pencraft pc-display-flex pc-justifyContent-flex-end pc-alignItems-center pc-reset buttonsContainerContainer-ThaN_w"><div class="buttonsContainer-SJBuep"><div class="pencraft pc-display-flex pc-gap-8 pc-justifyContent-flex-end pc-alignItems-center pc-reset navbar-buttons"><div class="pencraft pc-display-flex pc-gap-4 pc-reset"><span data-state="closed"><button tabindex="0" type="button" aria-label="Search" class="pencraft pc-reset pencraft iconButton-mq_Et5 iconButtonBase-dJGHgN buttonBase-GK1x3M buttonStyle-r7yGCK size_md-gCDS3o priority_tertiary-rlke8z"><svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-search"><circle cx="11" cy="11" r="8"></circle><path d="m21 21-4.3-4.3"></path></svg></button></span><button tabindex="0" type="button" aria-label="Share Publication" id="radix-P0-4" aria-haspopup="menu" aria-expanded="false" data-state="closed" class="pencraft pc-reset pencraft iconButton-mq_Et5 iconButtonBase-dJGHgN buttonBase-GK1x3M buttonStyle-r7yGCK size_md-gCDS3o priority_tertiary-rlke8z"><svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-share"><path d="M4 12v8a2 2 0 0 0 2 2h12a2 2 0 0 0 2-2v-8"></path><polyline points="16 6 12 2 8 6"></polyline><line x1="12" x2="12" y1="2" y2="15"></line></svg></button></div><button tabindex="0" type="button" data-testid="noncontributor-cta-button" class="pencraft pc-reset pencraft buttonBase-GK1x3M buttonText-X0uSmG buttonStyle-r7yGCK priority_primary-RfbeYt size_md-gCDS3o">Subscribe</button><button tabindex="0" data-native="true" type="button" data-href="https://substack.com/sign-in?redirect=%2Fp%2Fslo&amp;for_pub=alexewerlof" class="pencraft pc-reset pencraft buttonBase-GK1x3M buttonText-X0uSmG buttonStyle-r7yGCK priority_tertiary-rlke8z size_md-gCDS3o">Sign in</button></div></div></div></div></div><div style="background-color:#001426;height:94px;"></div></div></div><div><script nonce="-MFX1YSb2IeRINbXaYJYwQ" type="application/ld+json">{"@context":"https://schema.org","@type":"NewsArticle","url":"https://blog.alexewerlof.com/p/slo","mainEntityOfPage":"https://blog.alexewerlof.com/p/slo","headline":"SLO","description":"Dive into the fundamentals of Service Level Objectives (SLOs) with this guide. Understand SLOs, error budgets, and their practical implications through real-world examples. Learn to set and manage SLOs effectively with case studies on API service reliability.","image":[{"@type":"ImageObject","url":"https://substackcdn.com/image/fetch/f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F0ec62079-bcea-47fa-aafc-e3f7b6ed0f9a_1054x876.png"}],"datePublished":"2024-05-06T12:45:03+00:00","dateModified":"2024-05-06T12:45:03+00:00","isAccessibleForFree":false,"author":[{"@type":"Person","name":"Alex Ewerl\u00F6f","url":"https://substack.com/@alexewerlof","description":"Writes about technical leadership, growth mindset, and system reliability engineering. Senior Staff Engineer, MSc Systems Engineering from KTH, Stockholmer, dad, amateur artist. Read more here: https://www.alexewerlof.com/who","identifier":"user:87732486","sameAs":["https://twitter.com/alexewerlof"],"image":{"@type":"ImageObject","contentUrl":"https://substackcdn.com/image/fetch/$s_!IRtW!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg","thumbnailUrl":"https://substackcdn.com/image/fetch/$s_!IRtW!,w_128,h_128,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg"}}],"publisher":{"@type":"Organization","name":"Alex Ewerl\u00F6f Notes","url":"https://blog.alexewerlof.com","description":"Technical Leadership, Reliability Engineering, Growth","interactionStatistic":{"@type":"InteractionCounter","name":"Subscribers","interactionType":"https://schema.org/SubscribeAction","userInteractionCount":10000},"identifier":"pub:1002265","logo":{"@type":"ImageObject","url":"https://substackcdn.com/image/fetch/$s_!_Ur2!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png","contentUrl":"https://substackcdn.com/image/fetch/$s_!_Ur2!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png","thumbnailUrl":"https://substackcdn.com/image/fetch/$s_!_Ur2!,w_128,h_128,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png"},"image":{"@type":"ImageObject","url":"https://substackcdn.com/image/fetch/$s_!_Ur2!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png","contentUrl":"https://substackcdn.com/image/fetch/$s_!_Ur2!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png","thumbnailUrl":"https://substackcdn.com/image/fetch/$s_!_Ur2!,w_128,h_128,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png"},"sameAs":["https://twitter.com/alexewerlof"]},"interactionStatistic":[{"@type":"InteractionCounter","interactionType":"https://schema.org/LikeAction","userInteractionCount":19},{"@type":"InteractionCounter","interactionType":"https://schema.org/ShareAction","userInteractionCount":3},{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0}]}</script><script nonce="-MFX1YSb2IeRINbXaYJYwQ" type="application/ld+json">{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Alex Ewerl\u00F6f Notes","item":"https://blog.alexewerlof.com"},{"@type":"ListItem","position":2,"name":"SLO","item":"https://blog.alexewerlof.com/p/slo"}]}</script><div aria-label="Post" role="main" class="single-post-container"><div class="container"><div class="single-post"><div class="pencraft pc-display-contents pc-reset pubTheme-yiXxQA"><article class="typography newsletter-post post"><div role="region" aria-label="Post header" class="post-header"><div class="pencraft pc-display-flex pc-reset post-label"><a href="https://blog.alexewerlof.com/s/sre/?utm_source=substack&amp;utm_medium=menu" class="pencraft pc-reset color-secondary-ls1g8s line-height-20-t4M0El font-meta-MWBumP size-14-MLPa7j weight-medium-fw81nC transform-uppercase-yKDgcq reset-IxiVJZ meta-EgzBVA">Reliability Engineering</a></div><h1 dir="auto" class="post-title published title-X77sOw">SLO</h1><h3 dir="auto" class="subtitle subtitle-HEEcLo">Introduction to Service Level Objectives and their relationship with error budgets</h3><div aria-label="Post UFI" role="region" class="pencraft pc-display-flex pc-flexDirection-column pc-paddingBottom-16 pc-reset"><div class="pencraft pc-display-flex pc-paddingTop-16 pc-paddingBottom-16 pc-justifyContent-space-between pc-alignItems-center pc-reset"><div class="pencraft pc-display-flex pc-gap-12 pc-alignItems-center pc-reset byline-wrapper"><div class="pencraft pc-display-flex pc-reset"><div class="pencraft pc-display-flex pc-flexDirection-row pc-gap-8 pc-alignItems-center pc-justifyContent-flex-start pc-reset"><div style="--scale:36px;--offset:9px;--border-width:4.5px;" class="pencraft pc-display-flex pc-flexDirection-row pc-alignItems-center pc-justifyContent-flex-start pc-reset ltr-qDBmby"><a href="https://substack.com/@alexewerlof" aria-label="View Alex Ewerlöf's profile" class="pencraft pc-display-contents pc-reset"><div style="--scale:36px;" tabindex="0" class="pencraft pc-display-flex pc-width-36 pc-height-36 pc-justifyContent-center pc-alignItems-center pc-position-relative pc-reset bg-secondary-UUD3_J flex-auto-j3S2WA animate-XFJxE4 outline-detail-vcQLyr pc-borderRadius-full overflow-hidden-WdpwT6 sizing-border-box-DggLA4 pressable-sm-YIJFKJ showFocus-sk_vEm container-TAtrWj interactive-UkK0V6 avatar-u8q6xB last-JfNEJ_"><div style="--scale:36px;" title="Alex Ewerlöf" class="pencraft pc-display-flex pc-width-36 pc-height-36 pc-justifyContent-center pc-alignItems-center pc-position-relative pc-reset bg-secondary-UUD3_J flex-auto-j3S2WA outline-detail-vcQLyr pc-borderRadius-full overflow-hidden-WdpwT6 sizing-border-box-DggLA4 container-TAtrWj"><picture><source type="image/webp" srcset="https://substackcdn.com/image/fetch/$s_!IRtW!,w_36,h_36,c_fill,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg 1x, https://substackcdn.com/image/fetch/$s_!IRtW!,w_72,h_72,c_fill,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg 2x, https://substackcdn.com/image/fetch/$s_!IRtW!,w_108,h_108,c_fill,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg 3x"/><img src="https://substackcdn.com/image/fetch/$s_!IRtW!,w_36,h_36,c_fill,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg" alt="Alex Ewerlöf's avatar" srcset="https://substackcdn.com/image/fetch/$s_!IRtW!,w_36,h_36,c_fill,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg 1x, https://substackcdn.com/image/fetch/$s_!IRtW!,w_72,h_72,c_fill,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg 2x, https://substackcdn.com/image/fetch/$s_!IRtW!,w_108,h_108,c_fill,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg 3x" width="36" height="36" draggable="false" class="img-OACg1c object-fit-cover-u4ReeV pencraft pc-reset"/></picture></div></div></a></div></div></div><div class="pencraft pc-display-flex pc-flexDirection-column pc-reset"><div class="pencraft pc-reset color-primary-zABazT line-height-20-t4M0El font-meta-MWBumP size-11-NuY2Zx weight-medium-fw81nC transform-uppercase-yKDgcq reset-IxiVJZ meta-EgzBVA"><span style="min-width:0;" data-state="closed"><a href="https://substack.com/@alexewerlof" class="pencraft pc-reset decoration-hover-underline-ClDVRM reset-IxiVJZ">Alex Ewerlöf</a></span></div><div class="pencraft pc-display-flex pc-gap-4 pc-reset"><div class="pencraft pc-reset color-secondary-ls1g8s line-height-20-t4M0El font-meta-MWBumP size-11-NuY2Zx weight-medium-fw81nC transform-uppercase-yKDgcq reset-IxiVJZ meta-EgzBVA"><time datetime="2024-05-06T12:45:03.587Z" title="2024-05-06T12:45:03.587Z">May 06, 2024</time></div><div class="pencraft pc-reset color-secondary-ls1g8s line-height-20-t4M0El font-meta-MWBumP size-11-NuY2Zx weight-medium-fw81nC transform-uppercase-yKDgcq reset-IxiVJZ meta-EgzBVA">∙ Paid</div></div></div></div></div><div class="pencraft pc-display-flex pc-gap-16 pc-justifyContent-space-between pc-alignItems-center pc-reset flex-grow-rzmknG post-ufi"><div class="pencraft pc-display-flex pc-gap-8 pc-reset"><div class="like-button-container post-ufi-button style-button"><button tabindex="0" type="button" aria-label="Like (19)" aria-pressed="false" class="pencraft pc-reset pencraft post-ufi-button style-button has-label with-border"><svg aria-hidden="true" style="height:20px;width:20px;" width="20" height="20" viewBox="0 0 24 24" fill="#000000" stroke-width="2" stroke="#000" xmlns="http://www.w3.org/2000/svg" class="icon"><g><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-heart"><path d="M19 14c1.49-1.46 3-3.21 3-5.5A5.5 5.5 0 0 0 16.5 3c-1.76 0-3 .5-4.5 2-1.5-1.5-2.74-2-4.5-2A5.5 5.5 0 0 0 2 8.5c0 2.3 1.5 4.05 3 5.5l7 7Z"></path></svg></g></svg><div class="label">19</div></button></div><button tabindex="0" type="button" aria-label="View comments (0)" data-href="https://blog.alexewerlof.com/p/slo/comments" class="pencraft pc-reset pencraft post-ufi-button style-button post-ufi-comment-button no-label with-border"><svg aria-hidden="true" style="height:20px;width:20px;" width="20" height="20" viewBox="0 0 24 24" fill="#000000" stroke-width="2" stroke="#000" xmlns="http://www.w3.org/2000/svg" class="icon"><g><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-message-circle"><path d="M7.9 20A9 9 0 1 0 4 16.1L2 22Z"></path></svg></g></svg></button><button tabindex="0" type="button" id="radix-P0-27" aria-haspopup="menu" aria-expanded="false" data-state="closed" class="pencraft pc-reset pencraft post-ufi-button style-button has-label with-border"><svg aria-hidden="true" width="20" height="20" viewBox="0 0 20 20" fill="none" stroke-width="2" stroke="var(--color-fg-primary)" stroke-linecap="round" stroke-linejoin="round" xmlns="http://www.w3.org/2000/svg" class="icon"><g><path d="M2.53001 7.81595C3.49179 4.73911 6.43281 2.5 9.91173 2.5C13.1684 2.5 15.9537 4.46214 17.0852 7.23684L17.6179 8.67647M17.6179 8.67647L18.5002 4.26471M17.6179 8.67647L13.6473 6.91176M17.4995 12.1841C16.5378 15.2609 13.5967 17.5 10.1178 17.5C6.86118 17.5 4.07589 15.5379 2.94432 12.7632L2.41165 11.3235M2.41165 11.3235L1.5293 15.7353M2.41165 11.3235L6.38224 13.0882"></path></g></svg><div class="label">3</div></button></div><div class="pencraft pc-display-flex pc-gap-8 pc-reset"><button tabindex="0" type="button" class="pencraft pc-reset pencraft post-ufi-button style-button has-label with-border"><div class="label">Share</div></button></div></div></div></div><div><div class="dt-post-body"><div class="available-content"><div dir="auto" class="body markup"><p><span>Service Level Objective (SLO) sets the reliability expectation for the service based on how the service consumer perceives reliability (</span><a href="https://blog.alexewerlof.com/p/sli">SLI</a><span>).</span></p><p>One of the key ideas behind SLO is to shift the expectations from 100% reliability (which is not practical, and leads to disappointment, finger-pointing, and unreasonably high cost) to a number that is reasonable (e.g. 99%).</p><p><span>The difference is small (e.g. 1%) but it clarifies the error budget as a way to transparently balance the cost of reliability while controlling the risks of changing a system and setting the pace of those changes. The “pace” aspect comes in handy when doing </span><a href="https://blog.alexewerlof.com/p/wardley-maps-and-pace-layering-for">Pace Layering</a><span>, for example the critical services have a stricter reliability goal than the more experimental ones.</span></p><p><span>SLOs are internal </span><strong>goals</strong><span> that help teams make data-driven decisions about reliability and prioritize engineering work, such as balancing the speed of feature delivery with the need for stability </span></p><div class="captioned-image-container"><figure><a target="_blank" href="https://substackcdn.com/image/fetch/$s_!z_xD!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F2d3d3162-72c1-4b39-927a-a0a121508054_1033x1026.png" data-component-name="Image2ToDOM" class="image-link image2 is-viewable-img can-restack"><div class="image2-inset"><picture><source type="image/webp" srcset="https://substackcdn.com/image/fetch/$s_!z_xD!,w_424,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F2d3d3162-72c1-4b39-927a-a0a121508054_1033x1026.png 424w, https://substackcdn.com/image/fetch/$s_!z_xD!,w_848,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F2d3d3162-72c1-4b39-927a-a0a121508054_1033x1026.png 848w, https://substackcdn.com/image/fetch/$s_!z_xD!,w_1272,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F2d3d3162-72c1-4b39-927a-a0a121508054_1033x1026.png 1272w, https://substackcdn.com/image/fetch/$s_!z_xD!,w_1456,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F2d3d3162-72c1-4b39-927a-a0a121508054_1033x1026.png 1456w" sizes="100vw"/><img src="https://substackcdn.com/image/fetch/$s_!z_xD!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F2d3d3162-72c1-4b39-927a-a0a121508054_1033x1026.png" width="1033" height="1026" data-attrs="{&quot;src&quot;:&quot;https://substack-post-media.s3.amazonaws.com/public/images/2d3d3162-72c1-4b39-927a-a0a121508054_1033x1026.png&quot;,&quot;srcNoWatermark&quot;:null,&quot;fullscreen&quot;:null,&quot;imageSize&quot;:null,&quot;height&quot;:1026,&quot;width&quot;:1033,&quot;resizeWidth&quot;:null,&quot;bytes&quot;:159959,&quot;alt&quot;:null,&quot;title&quot;:null,&quot;type&quot;:&quot;image/png&quot;,&quot;href&quot;:null,&quot;belowTheFold&quot;:false,&quot;topImage&quot;:true,&quot;internalRedirect&quot;:null,&quot;isProcessing&quot;:false,&quot;align&quot;:null,&quot;offset&quot;:false}" alt srcset="https://substackcdn.com/image/fetch/$s_!z_xD!,w_424,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F2d3d3162-72c1-4b39-927a-a0a121508054_1033x1026.png 424w, https://substackcdn.com/image/fetch/$s_!z_xD!,w_848,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F2d3d3162-72c1-4b39-927a-a0a121508054_1033x1026.png 848w, https://substackcdn.com/image/fetch/$s_!z_xD!,w_1272,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F2d3d3162-72c1-4b39-927a-a0a121508054_1033x1026.png 1272w, https://substackcdn.com/image/fetch/$s_!z_xD!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F2d3d3162-72c1-4b39-927a-a0a121508054_1033x1026.png 1456w" sizes="100vw" fetchpriority="high" class="sizing-normal"/></picture><div class="image-link-expand"><div class="pencraft pc-display-flex pc-gap-8 pc-reset"><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container restack-image"><svg aria-hidden="true" width="20" height="20" viewBox="0 0 20 20" fill="none" stroke-width="1.5" stroke="var(--color-fg-primary)" stroke-linecap="round" stroke-linejoin="round" xmlns="http://www.w3.org/2000/svg"><g><path d="M2.53001 7.81595C3.49179 4.73911 6.43281 2.5 9.91173 2.5C13.1684 2.5 15.9537 4.46214 17.0852 7.23684L17.6179 8.67647M17.6179 8.67647L18.5002 4.26471M17.6179 8.67647L13.6473 6.91176M17.4995 12.1841C16.5378 15.2609 13.5967 17.5 10.1178 17.5C6.86118 17.5 4.07589 15.5379 2.94432 12.7632L2.41165 11.3235M2.41165 11.3235L1.5293 15.7353M2.41165 11.3235L6.38224 13.0882"></path></g></svg></button><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container view-image"><svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-maximize2 lucide-maximize-2"><polyline points="15 3 21 3 21 9"></polyline><polyline points="9 21 3 21 3 15"></polyline><line x1="21" x2="14" y1="3" y2="10"></line><line x1="3" x2="10" y1="21" y2="14"></line></svg></button></div></div></div></a></figure></div><p>There are three aspects that defining a SLO:</p><ol><li><p><strong>The value:</strong><span> usually a number like </span><code>99.9%</code></p></li><li><p><strong><a href="https://blog.alexewerlof.com/p/compliance-period">The compliance period</a><span> (also known as “window”):</span></strong><span> usually </span><code>30</code><span> days. This is the time window which is used to count events or time-slices in the past to calculate the SLS (</span><a href="https://blog.alexewerlof.com/p/sls">Service Level Status</a><span>).</span></p></li><li><p><strong><a href="https://blog.alexewerlof.com/p/sli-good">The boundaries</a><span> (optional):</span></strong><span> for SLIs that use thresholds for what good events look like (e.g., if a latency below </span><code>800ms</code><span> is considered good, the number 800ms is part of the threshold).</span></p></li></ol><p><em><span>Note: all three are used for </span><a href="https://blog.alexewerlof.com/p/multi-tiered-slos">multi-tiered SLOs</a><span> which tie to the same SLI.</span></em></p><p><span>SLO heavily impacts the non-functional requirements (</span><a href="https://blog.alexewerlof.com/p/nfr">NFR</a><span>) for how the technical solution is designed, built, operated, secured, maintained, and budgeted.</span></p><p><span>While SLO gets all the publicity, the </span><a href="https://blog.alexewerlof.com/p/error-budget">error budget</a><span> is the real hero of reliability engineering. If you remember from </span><a href="https://blog.alexewerlof.com/p/why-bother-with-sli-and-slo">why bother with service levels</a><span>, we are trying to shift the mindset from “systems should never fail” to understanding what failure is (SLI) and how much of it can be tolerated (error budget).</span></p><div class="captioned-image-container"><figure><a target="_blank" href="https://substackcdn.com/image/fetch/$s_!gF3S!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Faf604aef-6dca-4aee-8084-18d73ad061de_559x447.jpeg" data-component-name="Image2ToDOM" class="image-link image2 is-viewable-img can-restack"><div class="image2-inset"><picture><source type="image/webp" srcset="https://substackcdn.com/image/fetch/$s_!gF3S!,w_424,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Faf604aef-6dca-4aee-8084-18d73ad061de_559x447.jpeg 424w, https://substackcdn.com/image/fetch/$s_!gF3S!,w_848,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Faf604aef-6dca-4aee-8084-18d73ad061de_559x447.jpeg 848w, https://substackcdn.com/image/fetch/$s_!gF3S!,w_1272,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Faf604aef-6dca-4aee-8084-18d73ad061de_559x447.jpeg 1272w, https://substackcdn.com/image/fetch/$s_!gF3S!,w_1456,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Faf604aef-6dca-4aee-8084-18d73ad061de_559x447.jpeg 1456w" sizes="100vw"/><img src="https://substackcdn.com/image/fetch/$s_!gF3S!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Faf604aef-6dca-4aee-8084-18d73ad061de_559x447.jpeg" width="559" height="447" data-attrs="{&quot;src&quot;:&quot;https://substack-post-media.s3.amazonaws.com/public/images/af604aef-6dca-4aee-8084-18d73ad061de_559x447.jpeg&quot;,&quot;srcNoWatermark&quot;:null,&quot;fullscreen&quot;:null,&quot;imageSize&quot;:null,&quot;height&quot;:447,&quot;width&quot;:559,&quot;resizeWidth&quot;:null,&quot;bytes&quot;:null,&quot;alt&quot;:null,&quot;title&quot;:null,&quot;type&quot;:null,&quot;href&quot;:null,&quot;belowTheFold&quot;:true,&quot;topImage&quot;:false,&quot;internalRedirect&quot;:null,&quot;isProcessing&quot;:false,&quot;align&quot;:null,&quot;offset&quot;:false}" alt srcset="https://substackcdn.com/image/fetch/$s_!gF3S!,w_424,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Faf604aef-6dca-4aee-8084-18d73ad061de_559x447.jpeg 424w, https://substackcdn.com/image/fetch/$s_!gF3S!,w_848,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Faf604aef-6dca-4aee-8084-18d73ad061de_559x447.jpeg 848w, https://substackcdn.com/image/fetch/$s_!gF3S!,w_1272,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Faf604aef-6dca-4aee-8084-18d73ad061de_559x447.jpeg 1272w, https://substackcdn.com/image/fetch/$s_!gF3S!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Faf604aef-6dca-4aee-8084-18d73ad061de_559x447.jpeg 1456w" sizes="100vw" loading="lazy" class="sizing-normal"/></picture><div class="image-link-expand"><div class="pencraft pc-display-flex pc-gap-8 pc-reset"><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container restack-image"><svg aria-hidden="true" width="20" height="20" viewBox="0 0 20 20" fill="none" stroke-width="1.5" stroke="var(--color-fg-primary)" stroke-linecap="round" stroke-linejoin="round" xmlns="http://www.w3.org/2000/svg"><g><path d="M2.53001 7.81595C3.49179 4.73911 6.43281 2.5 9.91173 2.5C13.1684 2.5 15.9537 4.46214 17.0852 7.23684L17.6179 8.67647M17.6179 8.67647L18.5002 4.26471M17.6179 8.67647L13.6473 6.91176M17.4995 12.1841C16.5378 15.2609 13.5967 17.5 10.1178 17.5C6.86118 17.5 4.07589 15.5379 2.94432 12.7632L2.41165 11.3235M2.41165 11.3235L1.5293 15.7353M2.41165 11.3235L6.38224 13.0882"></path></g></svg></button><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container view-image"><svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-maximize2 lucide-maximize-2"><polyline points="15 3 21 3 21 9"></polyline><polyline points="9 21 3 21 3 15"></polyline><line x1="21" x2="14" y1="3" y2="10"></line><line x1="3" x2="10" y1="21" y2="14"></line></svg></button></div></div></div></a></figure></div><p>Error budget is the maximum percentage of failure that the service is allowed to have in a given period. It is directly tied to the SLO. In fact, it complements the SLO:</p><div data-component-name="Latex" class="pencraft pc-display-flex pc-paddingTop-4px pc-paddingBottom-4px pc-justifyContent-center pc-reset flex-grow-rzmknG latex-rendered"><div class="pencraft pc-display-flex pc-flexDirection-column pc-justifyContent-center pc-reset"><span style="display:block;">\(Error Budget = 100 - SLO\)</span></div></div><p><span>For example, if the SLO is </span><code>99%</code><span>, the </span><em>error budget</em><span> is </span><code>1%</code><span>. If SLO is </span><code>99.6%</code><span>, the </span><em>error budget</em><span> is </span><code>0.4%</code><span>.</span></p><h2 class="header-anchor-post">Example<div class="pencraft pc-display-flex pc-alignItems-center pc-position-absolute pc-reset header-anchor-parent"><div class="pencraft pc-display-contents pc-reset pubTheme-yiXxQA"><div id="§example" class="pencraft pc-reset header-anchor offset-top"></div><button tabindex="0" type="button" aria-label="Link" data-href="https://blog.alexewerlof.com/i/142248697/example" class="pencraft pc-reset pencraft iconButton-mq_Et5 iconButtonBase-dJGHgN buttonBase-GK1x3M buttonStyle-r7yGCK size_sm-G3LciD priority_secondary-S63h9o"><svg xmlns="http://www.w3.org/2000/svg" width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-link"><path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path><path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path></svg></button></div></div></h2><p>Let’s start simple by defining an SLO for an API (service) which is consumed by two teams: a mobile team and a web team (service consumers).</p><p>The mobile app and web are the interface towards users. The business makes money by charging the users a monthly fee (e.g., something like Netflix).</p><p><em><span>Note: since money is involved, there may be an </span><a href="https://blog.alexewerlof.com/p/sla">SLA</a><span> too, but it’s out of the scope of this article.</span></em></p><div class="captioned-image-container"><figure><a target="_blank" href="https://substackcdn.com/image/fetch/$s_!43pu!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F727459b6-ec69-4604-b92d-b2149780fce1_969x745.png" data-component-name="Image2ToDOM" class="image-link image2 is-viewable-img can-restack"><div class="image2-inset"><picture><source type="image/webp" srcset="https://substackcdn.com/image/fetch/$s_!43pu!,w_424,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F727459b6-ec69-4604-b92d-b2149780fce1_969x745.png 424w, https://substackcdn.com/image/fetch/$s_!43pu!,w_848,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F727459b6-ec69-4604-b92d-b2149780fce1_969x745.png 848w, https://substackcdn.com/image/fetch/$s_!43pu!,w_1272,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F727459b6-ec69-4604-b92d-b2149780fce1_969x745.png 1272w, https://substackcdn.com/image/fetch/$s_!43pu!,w_1456,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F727459b6-ec69-4604-b92d-b2149780fce1_969x745.png 1456w" sizes="100vw"/><img src="https://substackcdn.com/image/fetch/$s_!43pu!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F727459b6-ec69-4604-b92d-b2149780fce1_969x745.png" width="969" height="745" data-attrs="{&quot;src&quot;:&quot;https://substack-post-media.s3.amazonaws.com/public/images/727459b6-ec69-4604-b92d-b2149780fce1_969x745.png&quot;,&quot;srcNoWatermark&quot;:null,&quot;fullscreen&quot;:null,&quot;imageSize&quot;:null,&quot;height&quot;:745,&quot;width&quot;:969,&quot;resizeWidth&quot;:null,&quot;bytes&quot;:80576,&quot;alt&quot;:null,&quot;title&quot;:null,&quot;type&quot;:&quot;image/png&quot;,&quot;href&quot;:null,&quot;belowTheFold&quot;:true,&quot;topImage&quot;:false,&quot;internalRedirect&quot;:null,&quot;isProcessing&quot;:false,&quot;align&quot;:null,&quot;offset&quot;:false}" alt srcset="https://substackcdn.com/image/fetch/$s_!43pu!,w_424,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F727459b6-ec69-4604-b92d-b2149780fce1_969x745.png 424w, https://substackcdn.com/image/fetch/$s_!43pu!,w_848,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F727459b6-ec69-4604-b92d-b2149780fce1_969x745.png 848w, https://substackcdn.com/image/fetch/$s_!43pu!,w_1272,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F727459b6-ec69-4604-b92d-b2149780fce1_969x745.png 1272w, https://substackcdn.com/image/fetch/$s_!43pu!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F727459b6-ec69-4604-b92d-b2149780fce1_969x745.png 1456w" sizes="100vw" loading="lazy" class="sizing-normal"/></picture><div class="image-link-expand"><div class="pencraft pc-display-flex pc-gap-8 pc-reset"><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container restack-image"><svg aria-hidden="true" width="20" height="20" viewBox="0 0 20 20" fill="none" stroke-width="1.5" stroke="var(--color-fg-primary)" stroke-linecap="round" stroke-linejoin="round" xmlns="http://www.w3.org/2000/svg"><g><path d="M2.53001 7.81595C3.49179 4.73911 6.43281 2.5 9.91173 2.5C13.1684 2.5 15.9537 4.46214 17.0852 7.23684L17.6179 8.67647M17.6179 8.67647L18.5002 4.26471M17.6179 8.67647L13.6473 6.91176M17.4995 12.1841C16.5378 15.2609 13.5967 17.5 10.1178 17.5C6.86118 17.5 4.07589 15.5379 2.94432 12.7632L2.41165 11.3235M2.41165 11.3235L1.5293 15.7353M2.41165 11.3235L6.38224 13.0882"></path></g></svg></button><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container view-image"><svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-maximize2 lucide-maximize-2"><polyline points="15 3 21 3 21 9"></polyline><polyline points="9 21 3 21 3 15"></polyline><line x1="21" x2="14" y1="3" y2="10"></line><line x1="3" x2="10" y1="21" y2="14"></line></svg></button></div></div></div></a></figure></div><p>The mobile and web team want to hold the team behind the API (service provider) accountable for keeping the API available.</p><p><span>The service consumers in this example perceive the reliability of the API based on its uptime (i.e., a </span><a href="https://blog.alexewerlof.com/p/time-based-vs-event-based">time-based SLI</a><span>).</span></p><p>Together with the API team they agree to use a probe to check the API availability every minute </p><p><em>Note: there are many ways to measure availability. Pinging an end point every minute doesn’t give the best signal but it’s easy to start with.</em></p><p><span>They decided on an SLO window of </span><code>30 days</code><span> because the subscribers are charged on a monthly basis and the UX study has some data about how much failure the customers can put up with before they seriously consider cancelling their subscription.</span></p><p><span>The maximum downtime the web team can tolerate is </span><code>10 minutes</code><span> per month.</span></p><p><span>But the mobile app team can tolerate a maximum of </span><code>2 hours</code><span> downtime per month due to on-device caching in their implementation.</span></p><p>Here’s what we know:</p><ul><li><p><strong>Service</strong><span> = API</span></p></li><li><p><strong>Service Provider</strong><span> = the team behind the API</span></p></li><li><p><strong>Service Consumers</strong><span> = mobile app and web team</span></p></li><li><p><strong><a href="https://blog.alexewerlof.com/p/sli">Service Level Indicator</a></strong><span> = Availability. Ping the </span><code>/health</code><span> endpoint every minute (</span><a href="https://blog.alexewerlof.com/p/time-based-vs-event-based">time-based</a><span>)</span></p><ul><li><p><strong><a href="https://blog.alexewerlof.com/p/sli-good">Good</a></strong><span> = the number of probes that returns </span><code>HTTP 200</code></p></li><li><p><strong><a href="https://blog.alexewerlof.com/p/valid-vs-total">Valid</a></strong><span> = the number of probes sent during the compliance period</span></p></li></ul></li><li><p><strong><a href="https://blog.alexewerlof.com/p/compliance-period">Compliance Period</a></strong><a href="https://blog.alexewerlof.com/p/compliance-period"> (SLO window)</a><span> = </span><code>30 days</code><span> = </span><code>43800 minutes</code><span> (you can </span><a href="https://www.google.com/search?q=month+to+minutes">use Google</a><span> for these conversions)</span></p><ul><li><p><span>Rolling window: at any given time, we look at the past </span><code>43800 minutes</code><span>.</span></p></li></ul></li><li><p><strong><a href="https://blog.alexewerlof.com/p/error-budget">Error budget</a></strong><span> = </span><code>min(10m, 120m)</code><span> (the SLO needs to satisfy the requirement of the most demanding consumer.</span></p></li></ul><p><span>The API team checks the historical data for their availability metrics. We call that a </span><a href="https://blog.alexewerlof.com/p/sls">Service Level Status</a><span> (SLS) to distinguish it from the SLI which is a metric and SLO which is an objective.</span></p><p><span>The API team checked their historical uptime and learned that in the past </span><code>90 days (129600 minutes)</code><span>, they had a downtime of </span><code>85 minutes</code><span>. That’s what they’re comfortable to commit to (the status-quo):</span></p><div data-component-name="Latex" class="pencraft pc-display-flex pc-paddingTop-4px pc-paddingBottom-4px pc-justifyContent-center pc-reset flex-grow-rzmknG latex-rendered"><div class="pencraft pc-display-flex pc-flexDirection-column pc-justifyContent-center pc-reset"><span style="display:block;">\(SLS_{90d} = \frac { 129600-85 }{129600} \times 100 = 99.93\%\)</span></div></div><p>This is below the level that the web team can tolerate (10 minutes downtime in 30 days):</p><div data-component-name="Latex" class="pencraft pc-display-flex pc-paddingTop-4px pc-paddingBottom-4px pc-justifyContent-center pc-reset flex-grow-rzmknG latex-rendered"><div class="pencraft pc-display-flex pc-flexDirection-column pc-justifyContent-center pc-reset"><span style="display:block;">\(SLO_{web} = \frac { 43800-10 }{43800} \times 100 = 99.97\%\)</span></div></div><p>But it is above the level that the mobile team can tolerate (120 minutes downtime in 30 days):</p><div data-component-name="Latex" class="pencraft pc-display-flex pc-paddingTop-4px pc-paddingBottom-4px pc-justifyContent-center pc-reset flex-grow-rzmknG latex-rendered"><div class="pencraft pc-display-flex pc-flexDirection-column pc-justifyContent-center pc-reset"><span style="display:block;">\(SLO_{mobile} = \frac { 43800-120 }{43800} \times 100 = 99.72\%\)</span></div></div><p><span>So, we have </span><code>99.93%</code><span>, </span><code>99.97%</code><span>, and </span><code>9.72%</code><span>. Which one should we pick?</span></p><div class="captioned-image-container"><figure><a target="_blank" href="https://substackcdn.com/image/fetch/$s_!xH-H!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F0ec62079-bcea-47fa-aafc-e3f7b6ed0f9a_1054x876.png" data-component-name="Image2ToDOM" class="image-link image2 is-viewable-img can-restack"><div class="image2-inset"><picture><source type="image/webp" srcset="https://substackcdn.com/image/fetch/$s_!xH-H!,w_424,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F0ec62079-bcea-47fa-aafc-e3f7b6ed0f9a_1054x876.png 424w, https://substackcdn.com/image/fetch/$s_!xH-H!,w_848,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F0ec62079-bcea-47fa-aafc-e3f7b6ed0f9a_1054x876.png 848w, https://substackcdn.com/image/fetch/$s_!xH-H!,w_1272,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F0ec62079-bcea-47fa-aafc-e3f7b6ed0f9a_1054x876.png 1272w, https://substackcdn.com/image/fetch/$s_!xH-H!,w_1456,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F0ec62079-bcea-47fa-aafc-e3f7b6ed0f9a_1054x876.png 1456w" sizes="100vw"/><img src="https://substackcdn.com/image/fetch/$s_!xH-H!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F0ec62079-bcea-47fa-aafc-e3f7b6ed0f9a_1054x876.png" width="1054" height="876" data-attrs="{&quot;src&quot;:&quot;https://substack-post-media.s3.amazonaws.com/public/images/0ec62079-bcea-47fa-aafc-e3f7b6ed0f9a_1054x876.png&quot;,&quot;srcNoWatermark&quot;:null,&quot;fullscreen&quot;:null,&quot;imageSize&quot;:null,&quot;height&quot;:876,&quot;width&quot;:1054,&quot;resizeWidth&quot;:null,&quot;bytes&quot;:78810,&quot;alt&quot;:null,&quot;title&quot;:null,&quot;type&quot;:&quot;image/png&quot;,&quot;href&quot;:null,&quot;belowTheFold&quot;:true,&quot;topImage&quot;:false,&quot;internalRedirect&quot;:null,&quot;isProcessing&quot;:false,&quot;align&quot;:null,&quot;offset&quot;:false}" alt srcset="https://substackcdn.com/image/fetch/$s_!xH-H!,w_424,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F0ec62079-bcea-47fa-aafc-e3f7b6ed0f9a_1054x876.png 424w, https://substackcdn.com/image/fetch/$s_!xH-H!,w_848,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F0ec62079-bcea-47fa-aafc-e3f7b6ed0f9a_1054x876.png 848w, https://substackcdn.com/image/fetch/$s_!xH-H!,w_1272,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F0ec62079-bcea-47fa-aafc-e3f7b6ed0f9a_1054x876.png 1272w, https://substackcdn.com/image/fetch/$s_!xH-H!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F0ec62079-bcea-47fa-aafc-e3f7b6ed0f9a_1054x876.png 1456w" sizes="100vw" loading="lazy" class="sizing-normal"/></picture><div class="image-link-expand"><div class="pencraft pc-display-flex pc-gap-8 pc-reset"><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container restack-image"><svg aria-hidden="true" width="20" height="20" viewBox="0 0 20 20" fill="none" stroke-width="1.5" stroke="var(--color-fg-primary)" stroke-linecap="round" stroke-linejoin="round" xmlns="http://www.w3.org/2000/svg"><g><path d="M2.53001 7.81595C3.49179 4.73911 6.43281 2.5 9.91173 2.5C13.1684 2.5 15.9537 4.46214 17.0852 7.23684L17.6179 8.67647M17.6179 8.67647L18.5002 4.26471M17.6179 8.67647L13.6473 6.91176M17.4995 12.1841C16.5378 15.2609 13.5967 17.5 10.1178 17.5C6.86118 17.5 4.07589 15.5379 2.94432 12.7632L2.41165 11.3235M2.41165 11.3235L1.5293 15.7353M2.41165 11.3235L6.38224 13.0882"></path></g></svg></button><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container view-image"><svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-maximize2 lucide-maximize-2"><polyline points="15 3 21 3 21 9"></polyline><polyline points="9 21 3 21 3 15"></polyline><line x1="21" x2="14" y1="3" y2="10"></line><line x1="3" x2="10" y1="21" y2="14"></line></svg></button></div></div></div></a></figure></div><p><span>Of course, the API team prefers the smallest SLO (</span><code>99.72%</code><span>) because that gives them a higher error budget.</span></p><p>But that SLO is below the level that the web team needs with its current implementation. What can they do?</p><p><span>As we discussed in the </span><a href="https://blog.alexewerlof.com/p/lagom-slo">”lagom” SLO</a><span>, the web team has three options:</span></p><ol><li><p><strong>Be prepared for outage</strong></p></li><li><p><strong>Share the risk with their consumers (end users)</strong></p></li><li><p><strong>Negotiate with the API team</strong></p></li></ol><p>The negotiation is tricky because the service provider and service consumer have a conflict of interest.</p><ul><li><p><span>The provider wants to maximize the error budget and may use </span><a href="https://blog.alexewerlof.com/p/10x9">the rule of 10x/9</a><span> to their defense.</span></p></li><li><p>The consumer wants to maximize the SLO and uses the paying customer experience as an argument</p></li></ul><div class="subscription-widget-wrap"><div class="subscription-widget show-subscribe"><div class="preamble"><p>In a future article, we’ll talk about various SLO negotiation scenarios and techniques. Do you want to get it in your mailbox when it’s out?</p></div><div data-component-name="SubscribeWidget" class="subscribe-widget"><div class="pencraft pc-display-flex pc-justifyContent-center pc-reset"><div class="container-IpPqBD"><form action="/api/v1/free?nojs=true" method="post" novalidate class="form form-M5sC90"><input type="hidden" name="first_url" value/><input type="hidden" name="first_referrer" value/><input type="hidden" name="current_url"/><input type="hidden" name="current_referrer"/><input type="hidden" name="first_session_url" value/><input type="hidden" name="first_session_referrer" value/><input type="hidden" name="referral_code"/><input type="hidden" name="source" value="subscribe-widget-preamble"/><input type="hidden" name="referring_pub_id"/><input type="hidden" name="additional_referring_pub_ids"/><input type="hidden" name="source_post_id" value="142248697"/><div class="sideBySideWrap-vGXrwP"><div class="emailInputWrapper-QlA86j"><div class="pencraft pc-display-flex pc-minWidth-0 pc-position-relative pc-reset flex-auto-j3S2WA"><input name="email" placeholder="Type your email..." type="email" class="pencraft emailInput-OkIMeB input-y4v6N4 inputText-pV_yWb"/></div></div><button tabindex="0" type="submit" disabled class="pencraft pc-reset pencraft rightButton primary subscribe-btn button-VFSdkv buttonBase-GK1x3M"><span class="button-text ">Subscribe</span></button></div><div id="error-container"></div></form></div></div></div></div></div><p><span>Finding </span><em>impactful </em><span>SLI and </span><em>reasonable </em><span>SLO can be very tricky. As a Sr Staff Engineer responsible for a large organization (100+ teams), I have covered more than half of those teams with Service Level Workshops. I’ll be sharing the steps and experience </span><a href="https://blog.alexewerlof.com/p/service-level-workshops">in an upcoming post</a><span>.</span></p><div><hr/></div><p><em><a href="https://blog.alexewerlof.com/p/faq#%C2%A7payment">My monetization strategy</a><span> is to give away most content for free. However, these posts take anywhere from a few hours to days to draft, edit, research, illustrate, and publish. I pull these hours from my private time, vacation days and weekends. Recently I went down in working hours and salary by 10% to be able to spend more time on the newsletter. You can support me by sparing a few bucks for a paid subscription. As a token of appreciation, you get access to the Pro-Tips section as well as my book </span><a href="https://blog.alexewerlof.com/p/book-intro-reliability-engineering">Reliability Engineering Mindset</a><span>. Right now, you can get 20% off via </span><a href="https://blog.alexewerlof.com/protipsdiscount">this link</a><span>.</span></em></p><div data-attrs="{&quot;url&quot;:&quot;https://blog.alexewerlof.com/p/slo?utm_source=substack&amp;utm_medium=email&amp;utm_content=share&amp;action=share&quot;,&quot;text&quot;:&quot;Share&quot;}" data-component-name="CaptionedButtonToDOM" class="captioned-button-wrap"><div class="preamble"><p class="cta-caption">If you find this post insightful, please share it in your circles to inspire others.</p></div><p data-attrs="{&quot;url&quot;:&quot;https://blog.alexewerlof.com/p/slo?utm_source=substack&amp;utm_medium=email&amp;utm_content=share&amp;action=share&quot;,&quot;text&quot;:&quot;Share&quot;}" data-component-name="ButtonCreateButton" class="button-wrapper"><a href="https://blog.alexewerlof.com/p/slo?utm_source=substack&amp;utm_medium=email&amp;utm_content=share&amp;action=share" class="button primary"><span>Share</span></a></p></div><h2 class="header-anchor-post">Pro-Tips<div class="pencraft pc-display-flex pc-alignItems-center pc-position-absolute pc-reset header-anchor-parent"><div class="pencraft pc-display-contents pc-reset pubTheme-yiXxQA"><div id="§pro-tips" class="pencraft pc-reset header-anchor offset-top"></div><button tabindex="0" type="button" aria-label="Link" data-href="https://blog.alexewerlof.com/i/142248697/pro-tips" class="pencraft pc-reset pencraft iconButton-mq_Et5 iconButtonBase-dJGHgN buttonBase-GK1x3M buttonStyle-r7yGCK size_sm-G3LciD priority_secondary-S63h9o"><svg xmlns="http://www.w3.org/2000/svg" width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-link"><path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path><path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path></svg></button></div></div></h2></div></div></div><div data-testid="paywall" data-component-name="Paywall" role="region" aria-label="Paywall" class="paywall"><div style="--scale:64px;" class="pencraft pc-display-flex pc-width-64 pc-height-64 pc-justifyContent-center pc-alignItems-center pc-position-relative pc-reset bg-secondary-UUD3_J flex-auto-j3S2WA outline-detail-vcQLyr pc-borderRadius-full overflow-hidden-WdpwT6 sizing-border-box-DggLA4 container-TAtrWj paywall-unlock-avatar"><div style="--scale:64px;" title="User" class="pencraft pc-display-flex pc-width-64 pc-height-64 pc-justifyContent-center pc-alignItems-center pc-position-relative pc-reset bg-secondary-UUD3_J flex-auto-j3S2WA outline-detail-vcQLyr pc-borderRadius-full overflow-hidden-WdpwT6 sizing-border-box-DggLA4 container-TAtrWj"><picture><source type="image/webp" srcset="https://substackcdn.com/image/fetch/$s_!IRtW!,w_64,h_64,c_fill,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg 1x, https://substackcdn.com/image/fetch/$s_!IRtW!,w_128,h_128,c_fill,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg 2x, https://substackcdn.com/image/fetch/$s_!IRtW!,w_192,h_192,c_fill,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg 3x"/><img src="https://substackcdn.com/image/fetch/$s_!IRtW!,w_64,h_64,c_fill,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg" alt="User's avatar" srcset="https://substackcdn.com/image/fetch/$s_!IRtW!,w_64,h_64,c_fill,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg 1x, https://substackcdn.com/image/fetch/$s_!IRtW!,w_128,h_128,c_fill,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg 2x, https://substackcdn.com/image/fetch/$s_!IRtW!,w_192,h_192,c_fill,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg 3x" width="64" height="64" draggable="false" class="img-OACg1c object-fit-cover-u4ReeV pencraft pc-reset"/></picture></div></div><h2 class="paywall-title unlock-treatment-new">Continue reading this post for free, courtesy of Alex Ewerlöf.</h2><div class="paywall-cta"><a data-native="true"><button tabindex="0" type="button" class="pencraft pc-reset pencraft subscribe-btn subscribeButton-LcKYi7 paywall-cta-icon buttonBase-GK1x3M">Claim my free post</button></a></div><div class="paywall-secondary-cta"><a href="https://blog.alexewerlof.com/subscribe?simple=true&amp;next=https%3A%2F%2Fblog.alexewerlof.com%2Fp%2Fslo&amp;utm_source=paywall&amp;utm_medium=web&amp;utm_content=142248697&amp;just_signed_up=falsesimple=true&amp;utm_source=paywall&amp;utm_medium=email&amp;utm_content=142248697&amp;next=https://blog.alexewerlof.com/p/slo" data-native="true">Or purchase a paid subscription.</a></div></div></div></article></div></div></div><div class="pencraft pc-display-contents pc-reset pubTheme-yiXxQA"></div></div></div><div class="pencraft pc-display-flex pc-flexDirection-column pc-reset container-K5XPov"></div><div class="pencraft pc-display-contents pc-reset pubTheme-yiXxQA"><div class="footer-wrap compact-footer"><div class="visibility-check"></div><div class="footer custom-themed-background"><div class="pencraft pc-display-flex pc-gap-12 pc-alignItems-center pc-reset flex-grow-rzmknG"><div class="pencraft pc-display-flex pc-minWidth-0 pc-reset flex-grow-rzmknG nowrap-QngyoB"><span><span>© 2026 Alex Ewerlöf</span><span> · </span><a href="https://substack.com/privacy" target="_blank" rel="noopener" class="pencraft pc-reset decoration-underline-ClTkYc">Privacy</a><span> ∙ </span><a href="https://substack.com/tos" target="_blank" rel="noopener" class="pencraft pc-reset decoration-underline-ClTkYc">Terms</a><span> ∙ </span><a href="https://substack.com/ccpa#personal-data-collected" target="_blank" rel="noopener" class="pencraft pc-reset decoration-underline-ClTkYc">Collection notice</a></span></div><div class="pencraft pc-display-flex pc-reset"><div class="pencraft pc-display-flex pc-gap-8 pc-justifyContent-center pc-alignItems-center pc-reset footerButtons-ap9Sk7"><a data-native="true" href="https://substack.com/signup?utm_source=substack&amp;utm_medium=web&amp;utm_content=footer" class="footerSubstackCta-v5HWfj sizeSm-F_aC8H"><svg aria-hidden="true" width="1000" height="1000" viewBox="0 0 1000 1000" fill="#ff6719" stroke-width="1.8" stroke="none" xmlns="http://www.w3.org/2000/svg"><g><path d="M764.166 348.371H236.319V419.402H764.166V348.371Z"></path><path d="M236.319 483.752V813.999L500.231 666.512L764.19 813.999V483.752H236.319Z"></path><path d="M764.166 213H236.319V284.019H764.166V213Z"></path></g></svg> Start your Substack</a><a data-native="true" href="https://substack.com/app/app-store-redirect?utm_campaign=app-marketing&amp;utm_content=web-footer-button" class="footerSubstackCta-v5HWfj getTheApp-Yk3w1O noIcon-z7v9D8 sizeSm-F_aC8H sizeSmNoIcon-KRHkpZ">Get the app</a></div></div><div class="pencraft pc-display-flex pc-minWidth-0 pc-justifyContent-flex-end pc-reset flex-grow-rzmknG"><div translated class="pencraft pc-reset reset-IxiVJZ footer-slogan-blurb"><a href="https://substack.com" data-native="true">Substack</a> is the home for great culture</div></div></div></div></div></div></div><div role="region" aria-label="Notifications (F8)" tabindex="-1" style="pointer-events:none;"><ol tabindex="-1" style="--offset:0px;z-index:1000;" class="viewport-_BM4Bg"></ol></div><div></div><script suppressHydrationWarning nonce="-MFX1YSb2IeRINbXaYJYwQ">window.__staticRouterHydrationData = JSON.parse("{\"loaderData\":{},\"actionData\":null,\"errors\":null}");</script>
</div>
<script src="https://js.sentry-cdn.com/6c2ff3e3828e4017b7faf7b63e24cdf8.min.js" crossorigin="anonymous"></script>
<script nonce="-MFX1YSb2IeRINbXaYJYwQ">
window.Sentry && window.Sentry.onLoad(function() {
window.Sentry.init({
environment: window._preloads.sentry_environment,
dsn: window._preloads.sentry_dsn,
})
})
</script>
<script nonce="-MFX1YSb2IeRINbXaYJYwQ">window._preloads = JSON.parse("{\"cspNonce\":\"-MFX1YSb2IeRINbXaYJYwQ\",\"isEU\":false,\"language\":\"en\",\"country\":\"US\",\"leaderboardCountries\":[\"ES\",\"FR\",\"GB\",\"IT\",\"NL\"],\"enabledLeaderboardCountries\":[\"ES\",\"FR\",\"GB\",\"IT\",\"NL\"],\"userLocale\":{\"language\":\"en\",\"region\":\"US\",\"source\":\"accept-language\"},\"base_url\":\"https://blog.alexewerlof.com\",\"stripe_publishable_key\":\"pk_live_51QfnARLDSWi1i85FBpvw6YxfQHljOpWXw8IKi5qFWEzvW8HvoD8cqTulR9UWguYbYweLvA16P7LN6WZsGdZKrNkE00uGbFaOE3\",\"captcha_site_key\":\"6LeI15YsAAAAAPXyDcvuVqipba_jEFQCjz1PFQoz\",\"pub\":{\"apple_pay_disabled\":false,\"apex_domain\":null,\"author_id\":87732486,\"byline_images_enabled\":true,\"bylines_enabled\":true,\"chartable_token\":null,\"community_enabled\":true,\"copyright\":\"Alex Ewerl\u00F6f\",\"cover_photo_url\":\"https://substack-post-media.s3.amazonaws.com/public/images/ffddf167-cd34-41aa-9334-ad26acca3ed2_600x600.png\",\"created_at\":\"2022-07-14T22:27:58.683Z\",\"custom_domain_optional\":false,\"custom_domain\":\"blog.alexewerlof.com\",\"default_comment_sort\":\"oldest_first\",\"default_coupon\":null,\"default_group_coupon\":\"d8f4bfde\",\"default_show_guest_bios\":true,\"email_banner_url\":\"https://substack-post-media.s3.amazonaws.com/public/images/74f8e318-c490-4be2-b868-df0285fc2f3e_1100x220.png\",\"email_from_name\":\"Alex Ewerl\u00F6f Notes\",\"email_from\":null,\"embed_tracking_disabled\":false,\"explicit\":false,\"expose_paywall_content_to_search_engines\":true,\"fb_pixel_id\":null,\"fb_site_verification_token\":null,\"flagged_as_spam\":false,\"founding_subscription_benefits\":[\"1:1 chat, 60m video call\"],\"free_subscription_benefits\":[\"All the public posts\"],\"ga_pixel_id\":null,\"google_site_verification_token\":\"HIy4u2xUDZkIs6P0KJw9TSYeq7KqXSPAQvZIs9911qU\",\"google_tag_manager_token\":\"\",\"hero_image\":null,\"hero_text\":\"Technical Leadership, Reliability Engineering, Growth\",\"hide_intro_subtitle\":null,\"hide_intro_title\":null,\"hide_podcast_feed_link\":false,\"homepage_type\":\"newspaper\",\"id\":1002265,\"image_thumbnails_always_enabled\":false,\"invite_only\":false,\"hide_podcast_from_pub_listings\":false,\"hide_podcast_from_pub_listings_prior_to\":null,\"language\":\"en\",\"logo_url_wide\":\"https://substackcdn.com/image/fetch/$s_!3m6V!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fbd56dc7c-4b9f-43f2-99a1-ecc995284940_1200x256.png\",\"logo_url\":\"https://substackcdn.com/image/fetch/$s_!_Ur2!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png\",\"minimum_group_size\":2,\"moderation_enabled\":true,\"name\":\"Alex Ewerl\u00F6f Notes\",\"paid_subscription_benefits\":[\"The pro-tips on all articles\",\"Support spending my private time to write\",\"Access to full archive\"],\"parsely_pixel_id\":null,\"chartbeat_domain\":null,\"payments_state\":\"enabled\",\"paywall_free_trial_enabled\":true,\"podcast_art_url\":null,\"paid_podcast_episode_art_url\":null,\"podcast_byline\":null,\"podcast_description\":null,\"podcast_enabled\":false,\"podcast_feed_url\":null,\"podcast_title\":null,\"post_preview_limit\":null,\"primary_user_id\":87732486,\"require_clickthrough\":false,\"show_pub_podcast_tab\":false,\"show_recs_on_homepage\":true,\"subdomain\":\"alexewerlof\",\"subscriber_invites\":0,\"support_email\":null,\"theme_var_background_pop\":\"#786CFF\",\"theme_var_color_links\":false,\"theme_var_cover_bg_color\":null,\"trial_end_override\":null,\"twitter_pixel_id\":null,\"type\":\"newsletter\",\"post_reaction_faces_enabled\":true,\"is_personal_mode\":false,\"plans\":[{\"id\":\"monthly7_5eur\",\"object\":\"plan\",\"active\":true,\"aggregate_usage\":null,\"amount\":750,\"amount_decimal\":\"750\",\"billing_scheme\":\"per_unit\",\"created\":1728579524,\"currency\":\"eur\",\"interval\":\"month\",\"interval_count\":1,\"livemode\":true,\"metadata\":{\"substack\":\"yes\"},\"meter\":null,\"nickname\":\"\u20AC7.50 a month\",\"product\":\"prod_R0QYoetykRH93k\",\"tiers_mode\":null,\"transform_usage\":null,\"trial_period_days\":null,\"usage_type\":\"licensed\",\"currency_options\":{\"aud\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":1300,\"unit_amount_decimal\":\"1300\"},\"brl\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":4400,\"unit_amount_decimal\":\"4400\"},\"cad\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":1300,\"unit_amount_decimal\":\"1300\"},\"chf\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":800,\"unit_amount_decimal\":\"800\"},\"dkk\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":6000,\"unit_amount_decimal\":\"6000\"},\"eur\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":750,\"unit_amount_decimal\":\"750\"},\"gbp\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":700,\"unit_amount_decimal\":\"700\"},\"inr\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":82500,\"unit_amount_decimal\":\"82500\"},\"jpy\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":1500,\"unit_amount_decimal\":\"1500\"},\"mxn\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":15000,\"unit_amount_decimal\":\"15000\"},\"nok\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":8500,\"unit_amount_decimal\":\"8500\"},\"nzd\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":1500,\"unit_amount_decimal\":\"1500\"},\"pln\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":3300,\"unit_amount_decimal\":\"3300\"},\"sek\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":8500,\"unit_amount_decimal\":\"8500\"},\"usd\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":900,\"unit_amount_decimal\":\"900\"}}},{\"id\":\"yearly74eur\",\"object\":\"plan\",\"active\":true,\"aggregate_usage\":null,\"amount\":7400,\"amount_decimal\":\"7400\",\"billing_scheme\":\"per_unit\",\"created\":1728579524,\"currency\":\"eur\",\"interval\":\"year\",\"interval_count\":1,\"livemode\":true,\"metadata\":{\"substack\":\"yes\"},\"meter\":null,\"nickname\":\"\u20AC74 a year\",\"product\":\"prod_R0QYUJf9xqVpaq\",\"tiers_mode\":null,\"transform_usage\":null,\"trial_period_days\":null,\"usage_type\":\"licensed\",\"currency_options\":{\"aud\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":12500,\"unit_amount_decimal\":\"12500\"},\"brl\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":43500,\"unit_amount_decimal\":\"43500\"},\"cad\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":12000,\"unit_amount_decimal\":\"12000\"},\"chf\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":7000,\"unit_amount_decimal\":\"7000\"},\"dkk\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":55500,\"unit_amount_decimal\":\"55500\"},\"eur\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":7400,\"unit_amount_decimal\":\"7400\"},\"gbp\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":6500,\"unit_amount_decimal\":\"6500\"},\"inr\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":811000,\"unit_amount_decimal\":\"811000\"},\"jpy\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":14000,\"unit_amount_decimal\":\"14000\"},\"mxn\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":148000,\"unit_amount_decimal\":\"148000\"},\"nok\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":81500,\"unit_amount_decimal\":\"81500\"},\"nzd\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":15000,\"unit_amount_decimal\":\"15000\"},\"pln\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":32500,\"unit_amount_decimal\":\"32500\"},\"sek\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":82000,\"unit_amount_decimal\":\"82000\"},\"usd\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":8500,\"unit_amount_decimal\":\"8500\"}}},{\"id\":\"founding20000eur\",\"name\":\"founding20000eur\",\"nickname\":\"founding20000eur\",\"active\":true,\"amount\":20000,\"currency\":\"eur\",\"interval\":\"year\",\"interval_count\":1,\"metadata\":{\"substack\":\"yes\",\"founding\":\"yes\",\"no_coupons\":\"yes\",\"short_description\":\"VIP supporter\",\"short_description_english\":\"VIP supporter\",\"minimum\":\"20000\",\"minimum_local\":{\"usd\":23500,\"gbp\":17500,\"eur\":20000,\"cad\":32500,\"mxn\":394000,\"aud\":32500,\"brl\":119000,\"sek\":225500,\"chf\":19000,\"dkk\":149500,\"nok\":215500,\"inr\":2217000,\"jpy\":36000,\"nzd\":40000,\"pln\":86500}},\"currency_options\":{\"usd\":{\"unit_amount\":23500,\"tax_behavior\":\"unspecified\"},\"gbp\":{\"unit_amount\":17500,\"tax_behavior\":\"unspecified\"},\"eur\":{\"unit_amount\":20000,\"tax_behavior\":\"unspecified\"},\"cad\":{\"unit_amount\":32500,\"tax_behavior\":\"unspecified\"},\"mxn\":{\"unit_amount\":394000,\"tax_behavior\":\"unspecified\"},\"aud\":{\"unit_amount\":32500,\"tax_behavior\":\"unspecified\"},\"brl\":{\"unit_amount\":119000,\"tax_behavior\":\"unspecified\"},\"sek\":{\"unit_amount\":225500,\"tax_behavior\":\"unspecified\"},\"chf\":{\"unit_amount\":19000,\"tax_behavior\":\"unspecified\"},\"dkk\":{\"unit_amount\":149500,\"tax_behavior\":\"unspecified\"},\"nok\":{\"unit_amount\":215500,\"tax_behavior\":\"unspecified\"},\"inr\":{\"unit_amount\":2217000,\"tax_behavior\":\"unspecified\"},\"jpy\":{\"unit_amount\":36000,\"tax_behavior\":\"unspecified\"},\"nzd\":{\"unit_amount\":40000,\"tax_behavior\":\"unspecified\"},\"pln\":{\"unit_amount\":86500,\"tax_behavior\":\"unspecified\"}}}],\"stripe_user_id\":\"acct_1MAFmbEv9TeVut3s\",\"stripe_country\":\"SE\",\"stripe_publishable_key\":\"pk_live_51MAFmbEv9TeVut3sg6LOLDoGpzdvqtqZvasczL18isiPGcezpoD3DRMPDmivD2Qu12m0h0mpKUgIqx5cJZisTK1500fjcalFnx\",\"stripe_platform_account\":\"US\",\"automatic_tax_enabled\":false,\"author_name\":\"Alex Ewerl\u00F6f\",\"author_handle\":\"alexewerlof\",\"author_photo_url\":\"https://substackcdn.com/image/fetch/$s_!IRtW!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg\",\"author_bio\":\"Writes about technical leadership, growth mindset, and system reliability engineering. Senior Staff Engineer, MSc Systems Engineering from KTH, Stockholmer, dad, amateur artist. Read more here: https://www.alexewerlof.com/who\",\"twitter_screen_name\":\"alexewerlof\",\"has_custom_tos\":false,\"has_custom_privacy\":false,\"theme\":{\"background_pop_color\":\"#FFBC52\",\"web_bg_color\":\"#001426\",\"cover_bg_color\":\"#001426\",\"publication_id\":1002265,\"color_links\":null,\"font_preset_heading\":\"sans\",\"font_preset_body\":\"fancy_serif\",\"font_family_headings\":null,\"font_family_body\":null,\"font_family_ui\":null,\"font_size_body_desktop\":null,\"print_secondary\":null,\"custom_css_web\":null,\"custom_css_email\":null,\"home_hero\":\"feature-media\",\"home_posts\":\"custom\",\"home_show_top_posts\":true,\"hide_images_from_list\":false,\"home_hero_alignment\":\"left\",\"home_hero_show_podcast_links\":true,\"default_post_header_variant\":null,\"custom_header\":{\"layout\":\"stacked\",\"navStyle\":\"text\",\"navPosition\":\"bottom\",\"wordmarkLogoSize\":42},\"custom_footer\":{\"layout\":\"two-column\",\"backgroundColor\":\"#000C17\",\"publicationNameSize\":50,\"showPublicationName\":false,\"publicationNameStyle\":\"text\",\"publicationNamePosition\":\"bottom\",\"publicationNameBackgroundColor\":null},\"social_media_links\":{\"bluesky\":\"https://bsky.app/profile/alexewerlof.com\",\"youtube\":\"https://www.youtube.com/@alexewerlof\",\"linkedin\":\"https://www.linkedin.com/in/alexewerlof/\"},\"font_options\":{\"body\":\"merriweather_400\",\"heading\":\"heavy_sans\"},\"section_template\":null,\"custom_subscribe\":null,\"design_template\":null,\"design_template_options\":null},\"threads_v2_settings\":{\"first_thread_email_sent_at\":\"2023-02-12T20:30:37.079+00:00\",\"activated_at\":\"2023-02-12T20:30:06.164+00:00\",\"reader_thread_notifications_enabled\":true,\"create_thread_minimum_role\":\"paid\",\"photo_replies_enabled\":true,\"boost_free_subscriber_chat_preview_enabled\":false,\"push_suppression_enabled\":false},\"default_group_coupon_percent_off\":\"50.00\",\"default_group_coupon_include_founding\":false,\"pause_return_date\":null,\"has_posts\":true,\"has_recommendations\":true,\"first_post_date\":\"2020-09-24T11:28:00.000Z\",\"has_podcast\":false,\"has_free_podcast\":false,\"has_subscriber_only_podcast\":false,\"has_community_content\":true,\"rankingDetail\":\"Launched 4 years ago\",\"rankingDetailFreeIncluded\":\"Tens of thousands of subscribers\",\"rankingDetailOrderOfMagnitude\":10,\"rankingDetailFreeIncludedOrderOfMagnitude\":10000,\"rankingDetailFreeSubscriberCount\":\"Over 19,000 subscribers\",\"rankingDetailByLanguage\":{\"ar\":{\"rankingDetail\":\"\u062A\u0645 \u0627\u0644\u0625\u0637\u0644\u0627\u0642 4 years ago\"},\"ca\":{\"rankingDetail\":\"S\u2019ha llan\u00E7at fa 4 anys\"},\"da\":{\"rankingDetail\":\"Lancering 4 \u00E5r\"},\"de\":{\"rankingDetail\":\"vor 4 Jahren gelauncht\"},\"es\":{\"rankingDetail\":\"Lanzado hace 4 a\u00F1os\"},\"fr\":{\"rankingDetail\":\"Lanc\u00E9 il y a 4 ann\u00E9es\"},\"id\":{\"rankingDetail\":\"Diluncurkan 4 tahun yang lalu\"},\"ja\":{\"rankingDetail\":\"\u958B\u59CB\u65E5 4\u5E74\u524D\"},\"ko\":{\"rankingDetail\":\"4\uB144 \uC804\uC5D0 \uCD9C\uC2DC\"},\"nb\":{\"rankingDetail\":\"Lansert 4 \u00E5r\"},\"nl\":{\"rankingDetail\":\"Gelanceerd 4 jaar geleden\"},\"pl\":{\"rankingDetail\":\"Uruchomiono 4 lat temu\"},\"pt\":{\"rankingDetail\":\"Lan\u00E7ado 4 anos\"},\"pt-br\":{\"rankingDetail\":\"Lan\u00E7ado 4 anos\"},\"en-gb\":{\"rankingDetail\":\"Launched 4 years ago\"},\"it\":{\"rankingDetail\":\"Lanciato 4 anni\"},\"tr\":{\"rankingDetail\":\"4 y\u0131l ba\u015Flat\u0131ld\u0131\"},\"sv\":{\"rankingDetail\":\"Lanserad 4 \u00E5r sedan\"},\"fi\":{\"rankingDetail\":\"Launched 4 vuotta\"},\"is\":{\"rankingDetail\":\"Launched 4 \u00E1r\"},\"zh-hans\":{\"rankingDetail\":\"\u4E8E4 \u5E74\u524D\u4E0A\u7EBF\"},\"zh-hant\":{\"rankingDetail\":\"\u65BC 4 \u5E74\u524D \u63A8\u51FA\"},\"en\":{\"rankingDetail\":\"Launched 4 years ago\"}},\"freeSubscriberCount\":\"19,000\",\"freeSubscriberCountOrderOfMagnitude\":\"19K+\",\"author_bestseller_tier\":0,\"author_badge\":null,\"disable_monthly_subscriptions\":false,\"disable_annual_subscriptions\":false,\"hide_post_restacks\":false,\"notes_feed_enabled\":true,\"showIntroModule\":false,\"isPortraitLayout\":false,\"last_chat_post_at\":\"2025-10-31T11:34:19.438Z\",\"primary_profile_name\":\"Alex Ewerl\u00F6f\",\"primary_profile_photo_url\":\"https://substackcdn.com/image/fetch/$s_!IRtW!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg\",\"no_follow\":false,\"sponsorshipCampaigns\":{},\"paywall_chat\":\"free\",\"sections\":[{\"id\":67726,\"created_at\":\"2023-05-31T20:13:23.606Z\",\"updated_at\":\"2024-11-12T15:54:54.980Z\",\"publication_id\":1002265,\"name\":\"Technical Leadership\",\"description\":\"Technical Leadership, Staff Engineering, and impact without mandate\",\"slug\":\"tech-lead\",\"is_podcast\":false,\"is_live\":true,\"is_default_on\":true,\"sibling_rank\":0,\"port_status\":\"success\",\"logo_url\":null,\"hide_from_navbar\":false,\"email_from_name\":\"\",\"hide_posts_from_pub_listings\":false,\"email_banner_url\":null,\"cover_photo_url\":null,\"hide_intro_title\":false,\"hide_intro_subtitle\":false,\"ignore_publication_email_settings\":false,\"custom_config\":{},\"unifiedPodcastSettings\":null,\"showLinks\":[],\"podcastSettings\":null,\"pageTheme\":{\"id\":51608,\"publication_id\":1002265,\"section_id\":67726,\"page\":null,\"page_hero\":\"default\",\"page_posts\":\"grid\",\"show_podcast_links\":true,\"hero_alignment\":\"center\"},\"podcastPalette\":{\"DarkMuted\":{\"population\":72,\"rgb\":[73,153,137]},\"DarkVibrant\":{\"population\":6013,\"rgb\":[4,100,84]},\"LightMuted\":{\"population\":7,\"rgb\":[142,198,186]},\"LightVibrant\":{\"population\":3,\"rgb\":[166,214,206]},\"Muted\":{\"population\":6,\"rgb\":[92,164,156]},\"Vibrant\":{\"population\":5,\"rgb\":[76,164,146]}},\"spotify_podcast_settings\":null,\"unified_podcast_settings\":null},{\"id\":67723,\"created_at\":\"2023-05-31T19:57:24.859Z\",\"updated_at\":\"2024-03-22T13:16:12.203Z\",\"publication_id\":1002265,\"name\":\"Reliability Engineering\",\"description\":\"Concepts that help you with building reliable systems and architecture\",\"slug\":\"sre\",\"is_podcast\":false,\"is_live\":true,\"is_default_on\":true,\"sibling_rank\":1,\"port_status\":\"success\",\"logo_url\":null,\"hide_from_navbar\":false,\"email_from_name\":\"\",\"hide_posts_from_pub_listings\":false,\"email_banner_url\":null,\"cover_photo_url\":null,\"hide_intro_title\":false,\"hide_intro_subtitle\":false,\"ignore_publication_email_settings\":false,\"custom_config\":{},\"unifiedPodcastSettings\":null,\"showLinks\":[],\"podcastSettings\":null,\"pageTheme\":{\"id\":51609,\"publication_id\":1002265,\"section_id\":67723,\"page\":null,\"page_hero\":\"default\",\"page_posts\":\"grid\",\"show_podcast_links\":true,\"hero_alignment\":\"center\"},\"podcastPalette\":{\"DarkMuted\":{\"population\":72,\"rgb\":[73,153,137]},\"DarkVibrant\":{\"population\":6013,\"rgb\":[4,100,84]},\"LightMuted\":{\"population\":7,\"rgb\":[142,198,186]},\"LightVibrant\":{\"population\":3,\"rgb\":[166,214,206]},\"Muted\":{\"population\":6,\"rgb\":[92,164,156]},\"Vibrant\":{\"population\":5,\"rgb\":[76,164,146]}},\"spotify_podcast_settings\":null,\"unified_podcast_settings\":null},{\"id\":69986,\"created_at\":\"2023-06-17T13:00:28.926Z\",\"updated_at\":\"2023-06-17T13:00:28.926Z\",\"publication_id\":1002265,\"name\":\"Growth\",\"description\":\"Growth mindset, productivity, organizational growth, culture\",\"slug\":\"growth\",\"is_podcast\":false,\"is_live\":true,\"is_default_on\":true,\"sibling_rank\":2,\"port_status\":\"success\",\"logo_url\":null,\"hide_from_navbar\":false,\"email_from_name\":\"\",\"hide_posts_from_pub_listings\":false,\"email_banner_url\":null,\"cover_photo_url\":null,\"hide_intro_title\":false,\"hide_intro_subtitle\":false,\"ignore_publication_email_settings\":false,\"custom_config\":{},\"unifiedPodcastSettings\":null,\"showLinks\":[],\"podcastSettings\":null,\"pageTheme\":{\"id\":51610,\"publication_id\":1002265,\"section_id\":69986,\"page\":null,\"page_hero\":\"default\",\"page_posts\":\"grid\",\"show_podcast_links\":true,\"hero_alignment\":\"center\"},\"podcastPalette\":{\"DarkMuted\":{\"population\":72,\"rgb\":[73,153,137]},\"DarkVibrant\":{\"population\":6013,\"rgb\":[4,100,84]},\"LightMuted\":{\"population\":7,\"rgb\":[142,198,186]},\"LightVibrant\":{\"population\":3,\"rgb\":[166,214,206]},\"Muted\":{\"population\":6,\"rgb\":[92,164,156]},\"Vibrant\":{\"population\":5,\"rgb\":[76,164,146]}},\"spotify_podcast_settings\":null,\"unified_podcast_settings\":null},{\"id\":65305,\"created_at\":\"2023-05-14T08:17:44.620Z\",\"updated_at\":\"2023-05-14T08:17:44.620Z\",\"publication_id\":1002265,\"name\":\"Cartoons\",\"description\":\"The cartoons and doodles I draw from time to time\",\"slug\":\"cartoons\",\"is_podcast\":false,\"is_live\":true,\"is_default_on\":true,\"sibling_rank\":3,\"port_status\":\"success\",\"logo_url\":null,\"hide_from_navbar\":false,\"email_from_name\":\"\",\"hide_posts_from_pub_listings\":false,\"email_banner_url\":null,\"cover_photo_url\":null,\"hide_intro_title\":false,\"hide_intro_subtitle\":false,\"ignore_publication_email_settings\":false,\"custom_config\":{},\"unifiedPodcastSettings\":null,\"showLinks\":[],\"podcastSettings\":null,\"pageTheme\":{\"id\":51611,\"publication_id\":1002265,\"section_id\":65305,\"page\":null,\"page_hero\":\"default\",\"page_posts\":\"grid\",\"show_podcast_links\":true,\"hero_alignment\":\"center\"},\"podcastPalette\":{\"DarkMuted\":{\"population\":72,\"rgb\":[73,153,137]},\"DarkVibrant\":{\"population\":6013,\"rgb\":[4,100,84]},\"LightMuted\":{\"population\":7,\"rgb\":[142,198,186]},\"LightVibrant\":{\"population\":3,\"rgb\":[166,214,206]},\"Muted\":{\"population\":6,\"rgb\":[92,164,156]},\"Vibrant\":{\"population\":5,\"rgb\":[76,164,146]}},\"spotify_podcast_settings\":null,\"unified_podcast_settings\":null},{\"id\":192721,\"created_at\":\"2025-02-23T16:44:05.979Z\",\"updated_at\":\"2025-02-23T16:44:09.931Z\",\"publication_id\":1002265,\"name\":\"Code\",\"description\":\"Code and software development\",\"slug\":\"code\",\"is_podcast\":false,\"is_live\":true,\"is_default_on\":true,\"sibling_rank\":4,\"port_status\":\"success\",\"logo_url\":null,\"hide_from_navbar\":false,\"email_from_name\":\"\",\"hide_posts_from_pub_listings\":false,\"email_banner_url\":null,\"cover_photo_url\":null,\"hide_intro_title\":false,\"hide_intro_subtitle\":false,\"ignore_publication_email_settings\":false,\"custom_config\":{},\"unifiedPodcastSettings\":null,\"showLinks\":[],\"podcastSettings\":null,\"pageTheme\":{\"id\":51612,\"publication_id\":1002265,\"section_id\":192721,\"page\":null,\"page_hero\":\"default\",\"page_posts\":\"grid\",\"show_podcast_links\":true,\"hero_alignment\":\"center\"},\"podcastPalette\":{\"DarkMuted\":{\"population\":72,\"rgb\":[73,153,137]},\"DarkVibrant\":{\"population\":6013,\"rgb\":[4,100,84]},\"LightMuted\":{\"population\":7,\"rgb\":[142,198,186]},\"LightVibrant\":{\"population\":3,\"rgb\":[166,214,206]},\"Muted\":{\"population\":6,\"rgb\":[92,164,156]},\"Vibrant\":{\"population\":5,\"rgb\":[76,164,146]}},\"spotify_podcast_settings\":null,\"unified_podcast_settings\":null}],\"podcastTabInfo\":null,\"multipub_migration\":null,\"navigationBarItems\":[{\"id\":\"693b47dd-b5e5-4dbb-b7b3-891c9b2c1835\",\"publication_id\":1002265,\"sibling_rank\":0,\"link_title\":null,\"link_url\":null,\"section_id\":null,\"post_id\":null,\"is_hidden\":false,\"standard_key\":\"about\",\"post_tag_id\":null,\"parent_id\":null,\"is_group\":false,\"postTag\":null,\"children\":[],\"post\":null,\"section\":null},{\"id\":\"52ced5af-109a-4b1e-8910-89961a72b0a3\",\"publication_id\":1002265,\"sibling_rank\":0,\"link_title\":null,\"link_url\":null,\"section_id\":null,\"post_id\":null,\"is_hidden\":true,\"standard_key\":\"leaderboard\",\"post_tag_id\":null,\"parent_id\":null,\"is_group\":false,\"postTag\":null,\"children\":[],\"post\":null,\"section\":null},{\"id\":\"5657cede-0e4c-4869-8f2d-c73ebe2b3338\",\"publication_id\":1002265,\"sibling_rank\":0,\"link_title\":null,\"link_url\":null,\"section_id\":null,\"post_id\":null,\"is_hidden\":true,\"standard_key\":\"notes\",\"post_tag_id\":null,\"parent_id\":null,\"is_group\":false,\"postTag\":null,\"children\":[],\"post\":null,\"section\":null},{\"id\":\"d020acfa-0f0b-4afb-a793-8626297a59aa\",\"publication_id\":1002265,\"sibling_rank\":1,\"link_title\":null,\"link_url\":null,\"section_id\":null,\"post_id\":null,\"is_hidden\":true,\"standard_key\":\"chat\",\"post_tag_id\":null,\"parent_id\":null,\"is_group\":false,\"postTag\":null,\"children\":[],\"post\":null,\"section\":null},{\"id\":\"fc613bc6-10ab-41ef-9d39-a6a818fbb5ba\",\"publication_id\":1002265,\"sibling_rank\":2,\"link_title\":null,\"link_url\":null,\"section_id\":67726,\"post_id\":null,\"is_hidden\":null,\"standard_key\":null,\"post_tag_id\":null,\"parent_id\":null,\"is_group\":false,\"postTag\":null,\"children\":[],\"post\":null,\"section\":{\"id\":67726,\"slug\":\"tech-lead\",\"name\":\"Technical Leadership\",\"hide_from_navbar\":false,\"is_podcast\":false,\"logo_url\":null,\"newsletter_enabled\":null}},{\"id\":\"68d82a75-97a1-498b-b089-b9d606ee0f27\",\"publication_id\":1002265,\"sibling_rank\":3,\"link_title\":null,\"link_url\":null,\"section_id\":67723,\"post_id\":null,\"is_hidden\":null,\"standard_key\":null,\"post_tag_id\":null,\"parent_id\":null,\"is_group\":false,\"postTag\":null,\"children\":[],\"post\":null,\"section\":{\"id\":67723,\"slug\":\"sre\",\"name\":\"Reliability Engineering\",\"hide_from_navbar\":false,\"is_podcast\":false,\"logo_url\":null,\"newsletter_enabled\":null}},{\"id\":\"8a522501-651b-45bc-b881-3e2a2497ec29\",\"publication_id\":1002265,\"sibling_rank\":4,\"link_title\":null,\"link_url\":null,\"section_id\":69986,\"post_id\":null,\"is_hidden\":null,\"standard_key\":null,\"post_tag_id\":null,\"parent_id\":null,\"is_group\":false,\"postTag\":null,\"children\":[],\"post\":null,\"section\":{\"id\":69986,\"slug\":\"growth\",\"name\":\"Growth\",\"hide_from_navbar\":false,\"is_podcast\":false,\"logo_url\":null,\"newsletter_enabled\":null}},{\"id\":\"702039d0-d1f1-4070-adb7-6a88110ac904\",\"publication_id\":1002265,\"sibling_rank\":5,\"link_title\":null,\"link_url\":null,\"section_id\":65305,\"post_id\":null,\"is_hidden\":null,\"standard_key\":null,\"post_tag_id\":null,\"parent_id\":null,\"is_group\":false,\"postTag\":null,\"children\":[],\"post\":null,\"section\":{\"id\":65305,\"slug\":\"cartoons\",\"name\":\"Cartoons\",\"hide_from_navbar\":false,\"is_podcast\":false,\"logo_url\":null,\"newsletter_enabled\":null}},{\"id\":\"71e27c1f-1d9d-486d-bcce-3b707aedb0f6\",\"publication_id\":1002265,\"sibling_rank\":8,\"link_title\":\"FAQ\",\"link_url\":\"\",\"section_id\":null,\"post_id\":141786627,\"is_hidden\":null,\"standard_key\":null,\"post_tag_id\":null,\"parent_id\":null,\"is_group\":false,\"postTag\":null,\"children\":[],\"post\":{\"id\":141786627,\"slug\":\"faq\",\"title\":\"FAQ\",\"type\":\"page\"},\"section\":null},{\"id\":\"c3e7d81f-5147-498f-8317-72f318b996c3\",\"publication_id\":1002265,\"sibling_rank\":9999,\"link_title\":null,\"link_url\":null,\"section_id\":192721,\"post_id\":null,\"is_hidden\":null,\"standard_key\":null,\"post_tag_id\":null,\"parent_id\":null,\"is_group\":false,\"postTag\":null,\"children\":[],\"post\":null,\"section\":{\"id\":192721,\"slug\":\"code\",\"name\":\"Code\",\"hide_from_navbar\":false,\"is_podcast\":false,\"logo_url\":null,\"newsletter_enabled\":null}}],\"has_active_perks\":false,\"contributors\":[{\"name\":\"Alex Ewerl\u00F6f\",\"handle\":\"alexewerlof\",\"role\":\"admin\",\"owner\":true,\"user_id\":87732486,\"photo_url\":\"https://substackcdn.com/image/fetch/f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg\",\"bio\":\"Writes about technical leadership, growth mindset, and system reliability engineering. Senior Staff Engineer, MSc Systems Engineering from KTH, Stockholmer, dad, amateur artist. Read more here: https://www.alexewerlof.com/who\",\"status\":{\"bestsellerTier\":null,\"subscriberTier\":null,\"leaderboard\":null,\"vip\":false,\"badge\":null,\"subscriber\":null}}],\"threads_v2_enabled\":true,\"viralGiftsConfig\":{\"id\":\"549946e0-1129-4592-ba5f-6bcab8c6cb5d\",\"publication_id\":1002265,\"enabled\":true,\"gifts_per_user\":5,\"gift_length_months\":1,\"send_extra_gifts\":true,\"message\":\"Technical Leadership, personal growth, software\",\"created_at\":\"2022-12-01T16:46:31.467333+00:00\",\"updated_at\":\"2022-12-01T16:46:31.467333+00:00\",\"days_til_invite\":14,\"send_emails\":true,\"show_link\":null},\"no_index\":false,\"tier\":2,\"can_set_google_site_verification\":true,\"can_have_sitemap\":true,\"iap_advanced_plans\":[{\"sku\":\"c1LuwhX14kmFN5UK5J\",\"publication_id\":\"1002265\",\"is_active\":true,\"price_base_units\":1200,\"currency_alpha3\":\"usd\",\"period\":\"month\",\"created_at\":\"2026-07-07T19:37:06.872Z\",\"updated_at\":\"2026-07-07T19:37:06.872Z\",\"id\":\"1272592\",\"payout_amount_base_units\":86,\"alternate_currencies\":{\"aud\":1800,\"brl\":6500,\"cad\":1800,\"chf\":1000,\"dkk\":8000,\"eur\":1100,\"gbp\":900,\"mxn\":21000,\"nok\":12000,\"nzd\":2200,\"pln\":4500,\"sek\":12000},\"is_founding\":false,\"display_name\":\"Alex Ewerl\u00F6f Notes (Monthly)\",\"display_price\":\"$12\"},{\"sku\":\"MC73cNbFZtu7O35fUc\",\"publication_id\":\"1002265\",\"is_active\":true,\"price_base_units\":11500,\"currency_alpha3\":\"usd\",\"period\":\"year\",\"created_at\":\"2026-07-07T19:37:06.880Z\",\"updated_at\":\"2026-07-07T19:37:06.880Z\",\"id\":\"1272593\",\"payout_amount_base_units\":847,\"alternate_currencies\":{\"aud\":17000,\"brl\":59500,\"cad\":16500,\"chf\":9500,\"dkk\":75500,\"eur\":10500,\"gbp\":9000,\"mxn\":200000,\"nok\":112500,\"nzd\":20500,\"pln\":43500,\"sek\":111000},\"is_founding\":false,\"display_name\":\"Alex Ewerl\u00F6f Notes (Yearly)\",\"display_price\":\"$115\"}],\"iap_founding_plan\":{\"base_plan_id\":\"founding20000eur\",\"name\":\"VIP supporter\",\"minimum_amount\":27500,\"suggested_amount\":27500,\"currency_alpha3\":\"usd\",\"alternate_currencies\":{\"gbp\":{\"minimum_amount\":20500,\"suggested_amount\":20500},\"eur\":{\"minimum_amount\":24000,\"suggested_amount\":24000},\"cad\":{\"minimum_amount\":38500,\"suggested_amount\":38500},\"mxn\":{\"minimum_amount\":467000,\"suggested_amount\":467000},\"aud\":{\"minimum_amount\":38500,\"suggested_amount\":38500},\"brl\":{\"minimum_amount\":141000,\"suggested_amount\":141000},\"sek\":{\"minimum_amount\":267000,\"suggested_amount\":267000},\"chf\":{\"minimum_amount\":22500,\"suggested_amount\":22500},\"dkk\":{\"minimum_amount\":177500,\"suggested_amount\":177500},\"nok\":{\"minimum_amount\":255500,\"suggested_amount\":255500},\"inr\":{\"minimum_amount\":2628500,\"suggested_amount\":2628500},\"jpy\":{\"minimum_amount\":42500,\"suggested_amount\":42500},\"nzd\":{\"minimum_amount\":47500,\"suggested_amount\":47500},\"pln\":{\"minimum_amount\":103000,\"suggested_amount\":103000}}},\"founding_plan_name_english\":\"VIP supporter\",\"base_url\":\"https://blog.alexewerlof.com\",\"hostname\":\"blog.alexewerlof.com\",\"is_on_substack\":false,\"spotify_podcast_settings\":null,\"unified_podcast_settings\":null,\"podcastPalette\":{\"DarkMuted\":{\"population\":72,\"rgb\":[73,153,137]},\"DarkVibrant\":{\"population\":6013,\"rgb\":[4,100,84]},\"LightMuted\":{\"population\":7,\"rgb\":[142,198,186]},\"LightVibrant\":{\"population\":3,\"rgb\":[166,214,206]},\"Muted\":{\"population\":6,\"rgb\":[92,164,156]},\"Vibrant\":{\"population\":5,\"rgb\":[76,164,146]}},\"pageThemes\":{\"podcast\":null},\"supports_ip_content_unlock\":false,\"appTheme\":{\"colors\":{\"accent\":{\"name\":\"#ffbc52\",\"primary\":{\"r\":222,\"g\":158,\"b\":52,\"a\":1},\"primary_hover\":{\"r\":201,\"g\":140,\"b\":31,\"a\":1},\"primary_elevated\":{\"r\":201,\"g\":140,\"b\":31,\"a\":1},\"secondary\":{\"r\":222,\"g\":158,\"b\":52,\"a\":0.2},\"contrast\":{\"r\":255,\"g\":255,\"b\":255,\"a\":1},\"bg\":{\"r\":222,\"g\":158,\"b\":52,\"a\":0.2},\"bg_hover\":{\"r\":222,\"g\":158,\"b\":52,\"a\":0.3},\"dark\":{\"primary\":{\"r\":255,\"g\":188,\"b\":82,\"a\":1},\"primary_hover\":{\"r\":255,\"g\":210,\"b\":125,\"a\":1},\"primary_elevated\":{\"r\":255,\"g\":210,\"b\":125,\"a\":1},\"secondary\":{\"r\":255,\"g\":188,\"b\":82,\"a\":0.2},\"contrast\":{\"r\":0,\"g\":0,\"b\":0,\"a\":0.8},\"bg\":{\"r\":255,\"g\":188,\"b\":82,\"a\":0.2},\"bg_hover\":{\"r\":255,\"g\":188,\"b\":82,\"a\":0.3}}},\"fg\":{\"primary\":{\"r\":0,\"g\":0,\"b\":0,\"a\":0.8},\"secondary\":{\"r\":0,\"g\":0,\"b\":0,\"a\":0.6},\"tertiary\":{\"r\":0,\"g\":0,\"b\":0,\"a\":0.4},\"accent\":{\"r\":151,\"g\":97,\"b\":0,\"a\":1},\"dark\":{\"primary\":{\"r\":255,\"g\":255,\"b\":255,\"a\":0.9},\"secondary\":{\"r\":255,\"g\":255,\"b\":255,\"a\":0.6},\"tertiary\":{\"r\":255,\"g\":255,\"b\":255,\"a\":0.4},\"accent\":{\"r\":255,\"g\":188,\"b\":82,\"a\":1}}},\"bg\":{\"name\":\"#0085e5\",\"hue\":{\"r\":0,\"g\":133,\"b\":229,\"a\":1},\"tint\":{\"r\":0,\"g\":133,\"b\":229,\"a\":0.1},\"primary\":{\"r\":229.5,\"g\":242.8,\"b\":252.39999999999998,\"a\":1},\"primary_hover\":{\"r\":225,\"g\":238.29999999999998,\"b\":247.9,\"a\":1},\"primary_elevated\":{\"r\":225,\"g\":238.29999999999998,\"b\":247.9,\"a\":1},\"secondary\":{\"r\":214.2,\"g\":227.5,\"b\":237.1,\"a\":1},\"secondary_elevated\":{\"r\":184.9454280083347,\"g\":197.91521411644928,\"b\":207.26517218866366,\"a\":1},\"tertiary\":{\"r\":197.1,\"g\":210.4,\"b\":219.99999999999997,\"a\":1},\"quaternary\":{\"r\":163.79999999999998,\"g\":177.10000000000002,\"b\":186.70000000000002,\"a\":1},\"dark\":{\"primary\":{\"r\":19.8,\"g\":34,\"b\":44.5,\"a\":1},\"primary_hover\":{\"r\":24.3,\"g\":38.50000000000001,\"b\":48.99999999999999,\"a\":1},\"primary_elevated\":{\"r\":24.3,\"g\":38.50000000000001,\"b\":48.99999999999999,\"a\":1},\"secondary\":{\"r\":31.5,\"g\":46.60000000000001,\"b\":56.2,\"a\":1},\"secondary_elevated\":{\"r\":38.73972711589789,\"g\":54.076229834048654,\"b\":63.89709451363946,\"a\":1},\"tertiary\":{\"r\":48.6,\"g\":62.8,\"b\":72.4,\"a\":1},\"quaternary\":{\"r\":81.00000000000001,\"g\":95.2,\"b\":104.80000000000001,\"a\":1}}}}},\"portalAppTheme\":{\"colors\":{\"accent\":{\"name\":\"#FFBC52\",\"primary\":{\"r\":255,\"g\":188,\"b\":82,\"a\":1},\"primary_hover\":{\"r\":255,\"g\":178,\"b\":56,\"a\":1},\"primary_elevated\":{\"r\":255,\"g\":188,\"b\":82,\"a\":1},\"secondary\":{\"r\":255,\"g\":188,\"b\":82,\"a\":1},\"contrast\":{\"r\":255,\"g\":255,\"b\":255,\"a\":1},\"bg\":{\"r\":255,\"g\":103,\"b\":25,\"a\":0.2},\"bg_hover\":{\"r\":255,\"g\":103,\"b\":25,\"a\":0.3},\"dark\":{\"name\":\"#FFBC52\",\"primary\":{\"r\":255,\"g\":188,\"b\":82,\"a\":1},\"primary_hover\":{\"r\":255,\"g\":178,\"b\":56,\"a\":1},\"primary_elevated\":{\"r\":255,\"g\":188,\"b\":82,\"a\":1},\"secondary\":{\"r\":255,\"g\":188,\"b\":82,\"a\":1},\"contrast\":{\"r\":255,\"g\":255,\"b\":255,\"a\":1},\"bg\":{\"r\":255,\"g\":103,\"b\":25,\"a\":0.2},\"bg_hover\":{\"r\":255,\"g\":103,\"b\":25,\"a\":0.3}}},\"fg\":{\"primary\":{\"r\":226,\"g\":232,\"b\":237,\"a\":1},\"secondary\":{\"r\":153,\"g\":161,\"b\":168,\"a\":1},\"tertiary\":{\"r\":109,\"g\":120,\"b\":130,\"a\":1},\"accent\":{\"r\":255,\"g\":188,\"b\":82,\"a\":1},\"dark\":{\"primary\":{\"r\":226,\"g\":232,\"b\":237,\"a\":1},\"secondary\":{\"r\":153,\"g\":161,\"b\":168,\"a\":1},\"tertiary\":{\"r\":109,\"g\":120,\"b\":130,\"a\":1},\"accent\":{\"r\":255,\"g\":188,\"b\":82,\"a\":1}}},\"bg\":{\"name\":\"#001426\",\"hue\":{\"r\":0,\"g\":20,\"b\":38,\"a\":1},\"tint\":{\"r\":0,\"g\":20,\"b\":38,\"a\":1},\"primary\":{\"r\":0,\"g\":20,\"b\":38,\"a\":1},\"primary_hover\":{\"r\":15,\"g\":34,\"b\":51,\"a\":1},\"primary_elevated\":{\"r\":15,\"g\":34,\"b\":51,\"a\":1},\"secondary\":{\"r\":15,\"g\":34,\"b\":51,\"a\":1},\"secondary_elevated\":{\"r\":34,\"g\":52,\"b\":67,\"a\":1},\"tertiary\":{\"r\":34,\"g\":52,\"b\":67,\"a\":1},\"quaternary\":{\"r\":72,\"g\":86,\"b\":99,\"a\":1},\"dark\":{\"name\":\"#001426\",\"hue\":{\"r\":0,\"g\":20,\"b\":38,\"a\":1},\"tint\":{\"r\":0,\"g\":20,\"b\":38,\"a\":1},\"primary\":{\"r\":0,\"g\":20,\"b\":38,\"a\":1},\"primary_hover\":{\"r\":15,\"g\":34,\"b\":51,\"a\":1},\"primary_elevated\":{\"r\":15,\"g\":34,\"b\":51,\"a\":1},\"secondary\":{\"r\":15,\"g\":34,\"b\":51,\"a\":1},\"secondary_elevated\":{\"r\":34,\"g\":52,\"b\":67,\"a\":1},\"tertiary\":{\"r\":34,\"g\":52,\"b\":67,\"a\":1},\"quaternary\":{\"r\":72,\"g\":86,\"b\":99,\"a\":1}}},\"wordmark_bg\":{\"r\":0,\"g\":20,\"b\":38,\"a\":1},\"is_dark\":true},\"fonts\":{\"heading\":\"heavy_sans\",\"body\":\"merriweather_400\"}},\"logoPalette\":{\"Vibrant\":{\"rgb\":[252,188,84],\"population\":5509},\"DarkVibrant\":{\"rgb\":[4,20,36],\"population\":556},\"LightVibrant\":{\"rgb\":[244,181,84],\"population\":7},\"Muted\":{\"rgb\":[124,100,60],\"population\":1},\"DarkMuted\":{\"rgb\":[80,71,52],\"population\":65},\"LightMuted\":{\"rgb\":[143.75274725274724,90.7912087912088,9.247252747252743],\"population\":0}},\"section\":{\"id\":67723,\"created_at\":\"2023-05-31T19:57:24.859Z\",\"updated_at\":\"2024-03-22T13:16:12.203Z\",\"publication_id\":1002265,\"name\":\"Reliability Engineering\",\"description\":\"Concepts that help you with building reliable systems and architecture\",\"slug\":\"sre\",\"is_podcast\":false,\"is_live\":true,\"is_default_on\":true,\"sibling_rank\":1,\"port_status\":\"success\",\"logo_url\":null,\"hide_from_navbar\":false,\"email_from_name\":\"\",\"hide_posts_from_pub_listings\":false,\"email_banner_url\":null,\"cover_photo_url\":null,\"hide_intro_title\":false,\"hide_intro_subtitle\":false,\"ignore_publication_email_settings\":false,\"custom_config\":{},\"unifiedPodcastSettings\":null,\"showLinks\":[],\"podcastSettings\":null,\"pageTheme\":{\"id\":51609,\"publication_id\":1002265,\"section_id\":67723,\"page\":null,\"page_hero\":\"default\",\"page_posts\":\"grid\",\"show_podcast_links\":true,\"hero_alignment\":\"center\"},\"podcastPalette\":{\"DarkMuted\":{\"population\":72,\"rgb\":[73,153,137]},\"DarkVibrant\":{\"population\":6013,\"rgb\":[4,100,84]},\"LightMuted\":{\"population\":7,\"rgb\":[142,198,186]},\"LightVibrant\":{\"population\":3,\"rgb\":[166,214,206]},\"Muted\":{\"population\":6,\"rgb\":[92,164,156]},\"Vibrant\":{\"population\":5,\"rgb\":[76,164,146]}},\"spotify_podcast_settings\":null,\"unified_podcast_settings\":null}},\"confirmedLogin\":false,\"hide_intro_popup\":false,\"block_auto_login\":false,\"domainInfo\":{\"isSubstack\":false,\"customDomain\":\"blog.alexewerlof.com\"},\"experimentFeatures\":{},\"experimentExposures\":{},\"siteConfigs\":{\"score_upsell_email\":\"control\",\"first_chat_email_enabled\":true,\"new_commenter_approval\":false,\"pub_update_opennode_api_key\":false,\"notes_video_max_duration_minutes\":15,\"show_content_label_age_gating_in_feed\":false,\"zendesk_automation_cancellations\":false,\"mfa_action_box_enabled\":false,\"publication_max_bylines\":35,\"no_contest_charge_disputes\":false,\"scheduled_post_share_assets_enabled\":false,\"publication_tabs_reorder\":false,\"comp_expiry_email_new_copy\":\"NONE\",\"free_unlock_required\":false,\"enable_section_group_pages\":false,\"enable_post_summarization\":false,\"live_stream_host_warning_message\":\"\",\"bitcoin_enabled\":false,\"minimum_ios_os_version\":\"17.0.0\",\"show_entire_square_image\":false,\"hide_subscriber_count\":false,\"fit_in_live_stream_player\":false,\"publication_author_display_override\":\"\",\"enable_saved_segments\":true,\"generate_pdf_tax_report\":false,\"hide_post_sidebar\":false,\"show_generic_post_importer\":false,\"enable_pledges_modal\":true,\"community_automod_non_english_enabled\":true,\"audio_clips_enabled\":false,\"enable_videos_page\":false,\"exempt_from_gtm_filter\":false,\"group_sections_and_podcasts_in_menu\":false,\"boost_optin_modal_enabled\":true,\"standards_and_enforcement_features_enabled\":false,\"pub_creation_captcha_behavior\":\"risky_pubs_or_rate_limit\",\"post_blogspot_importer\":false,\"enable_high_res_background_uploading\":false,\"pub_tts_override\":\"default\",\"disable_monthly_subscriptions\":false,\"skip_welcome_email\":false,\"chat_reader_thread_notification_default\":false,\"scheduled_pinned_posts\":false,\"disable_redirect_outbound_utm_params\":false,\"reader_gift_referrals_enabled\":true,\"dont_show_guest_byline\":false,\"like_comments_enabled\":true,\"enable_theme_editor_deferred_saves\":false,\"enable_sponsorship_campaigns_advanced\":false,\"temporal_livestream_ended_draft\":true,\"enable_pangram_ai_detection\":true,\"fallback_to_archive_search_on_section_pages\":false,\"livekit_track_egress_custom_base_url\":\"http://livekit-egress-custom-recorder-participant-test.s3-website-us-east-1.amazonaws.com\",\"welcome_screen_blurb_override\":\"\",\"like_posts_enabled\":true,\"twitter_player_card_enabled\":true,\"feed_promoted_user\":false,\"show_note_stats_for_all_notes\":false,\"section_specific_csv_imports_enabled\":false,\"disable_podcast_feed_description_cta\":false,\"bypass_profile_substack_logo_detection\":false,\"use_preloaded_player_sources\":false,\"list_pruning_enabled\":false,\"facebook_connect\":false,\"opt_in_to_sections_during_subscribe\":false,\"underlined_colored_links\":false,\"enable_efficient_digest_embed\":false,\"enable_aligned_images\":false,\"max_image_upload_mb\":64,\"threads_suggested_ios_version\":null,\"pledges_disabled\":false,\"threads_minimum_ios_version\":812,\"hide_podcast_email_setup_link\":false,\"subscribe_captcha_behavior\":\"default\",\"publication_ban_sample_rate\":0,\"custom_themes_substack_subscribe_modal\":false,\"ios_post_share_assets_screenshot_trigger\":\"control\",\"opt_in_to_sections_during_subscribe_include_main_pub_newsletter\":false,\"continue_support_cta_in_newsletter_emails\":false,\"bloomberg_syndication_enabled\":false,\"allow_document_freeze\":false,\"test_age_gate_user\":false,\"podcast_main_feed_is_firehose\":false,\"pub_app_incentive_gift\":\"\",\"no_embed_redirect\":false,\"customized_email_from_name_for_new_follow_emails\":\"treatment\",\"spotify_open_access_sandbox_mode\":false,\"disable_custom_nav_menu\":false,\"enable_livestream_name_cards\":false,\"fullstory_enabled\":false,\"chat_reply_poll_interval\":3,\"thefp_enable_email_upsell_banner\":false,\"force_pub_links_to_use_subdomain\":false,\"always_show_cookie_banner\":false,\"hide_media_download_option\":false,\"hide_post_restacks\":false,\"feed_item_source_debug_mode\":false,\"twitter_embed_video_playback_enabled\":false,\"publication_homepage_title_display_override\":\"\",\"enable_email_automation_stats\":false,\"post_preview_highlight_byline\":false,\"4k_video\":false,\"enable_islands_section_intent_screen\":false,\"post_metering_enabled\":false,\"notifications_disabled\":\"\",\"cross_post_notification_threshold\":1000,\"facebook_connect_prod_app\":true,\"force_into_pymk_ranking\":false,\"minimum_android_version\":756,\"group_size_change_notification_email_enabled\":false,\"enable_transcription_translations\":false,\"use_og_image_as_twitter_image_for_post_previews\":false,\"always_use_podcast_channel_art_as_episode_art_in_rss\":false,\"seo_tier_override\":\"NONE\",\"editor_role_enabled\":false,\"no_follow_links\":false,\"publisher_api_enabled\":false,\"zendesk_support_priority\":\"default\",\"enable_post_clips_stats\":false,\"enable_subscriber_referrals_awards\":true,\"ios_profile_themes_feed_permalink_enabled\":false,\"reader_survey_during_subscribe_enabled\":true,\"use_publication_language_for_transcription\":false,\"show_substack_funded_gifts_tooltip\":true,\"disable_ai_transcription\":false,\"per_pub_notification_settings\":false,\"live_stream_creation_enabled\":true,\"disable_card_element_in_europe\":false,\"web_growth_item_promotion_threshold\":0,\"bundle_subscribe_enabled\":false,\"web_vitals_sample_rate\":0,\"allow_live_stream_auto_takedown\":\"true\",\"mobile_publication_attachments_enabled\":false,\"enable_design_templates_events_page\":false,\"enable_survey_response_crm_filters\":false,\"disable_personal_substack_initialization\":false,\"section_specific_welcome_pages\":false,\"local_payment_methods\":\"control\",\"publisher_api_cancel_comp\":false,\"posts_in_rss_feed\":20,\"publisher_dashboard_section_selector\":false,\"reader_surveys_platform_question_order\":\"36,1,4,2,3,5,6,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35\",\"login_guard_app_link_in_email\":true,\"community_moderators_enabled\":false,\"enable_custom_theme\":false,\"monthly_sub_is_one_off\":false,\"unread_notes_activity_digest\":\"control\",\"display_cookie_settings\":false,\"welcome_page_query_params\":false,\"enable_free_podcast_urls\":false,\"comp_expiry_emails_disabled\":false,\"enable_description_on_polls\":false,\"use_microlink_for_instagram_embeds\":false,\"free_signup_confirmation_behavior\":\"with_email_validation\",\"ios_post_stats_for_admins\":false,\"enable_design_templates\":false,\"use_livestream_post_media_composition\":true,\"section_specific_preambles\":false,\"pub_export_temp_disable\":false,\"show_menu_on_posts\":false,\"ios_post_subscribe_web_routing\":true,\"enable_pangram_detection_settings\":false,\"freewalls_enabled_web\":false,\"app_onboarding_survey_email\":false,\"republishing_enabled\":false,\"app_mode\":false,\"show_phone_banner\":false,\"minimum_ios_version\":2200,\"enable_author_pages\":false,\"enable_decagon_chat\":true,\"first_month_upsell\":\"control\",\"new_user_checklist_enabled\":\"use_follower_count\",\"disable_high_res_recording\":false,\"latex_upgraded_inline\":false,\"anonymous_post_metering_enabled\":false,\"rss_verification_code\":\"\",\"notification_post_emails\":\"experiment\",\"chat_suppress_contributor_push_option_enabled\":false,\"enable_subscriber_tags\":true,\"media_feed_app_prepend_inbox_limit\":0,\"export_hooks_enabled\":false,\"audio_encoding_bitrate\":null,\"extra_seats_coupon_type\":false,\"post_subdomain_universal_links\":false,\"post_import_max_file_size\":26214400,\"feed_promoted_video_publication\":false,\"livekit_reconnect_slate_url\":\"https://mux-livestream-assets.s3.us-east-1.amazonaws.com/custom-disconnect-slate-tall.png\",\"exclude_from_pymk_suggestions\":false,\"publication_ranking_variant\":\"experiment\",\"disable_annual_subscriptions\":false,\"hack_jane_manchun_wong\":true,\"android_enable_auto_gain_control\":true,\"allow_coupons_on_upgrade\":false,\"test_au_age_gate_user\":false,\"pub_auto_moderation_enabled\":false,\"disable_live_stream_ai_trimming_by_default\":false,\"disable_deletion\":false,\"livekit_egress_custom_base_url\":\"http://livekit-egress-custom-recorder.s3-website-us-east-1.amazonaws.com\",\"clip_focused_video_upload_flow\":false,\"live_stream_max_guest_users\":2,\"android_upgrade_alert_dialog_reincarnated\":true,\"enable_video_seo_data\":false,\"can_reimport_unsubscribed_users_with_2x_optin\":false,\"founding_upgrade_during_gift_disabled\":false,\"thefp_enable_section_groups\":false,\"review_incoming_email\":\"default\",\"enable_founding_gifts\":false,\"enable_sponsorship_campaigns\":false,\"thefp_forum_polls_enabled\":false,\"thefp_enable_embed_media_links\":false,\"sort_modal_search_results\":false,\"default_thumbnail_time\":10,\"load_test_unichat\":false,\"live_stream_head_alignment_guide\":false,\"free_press_combo_subscribe_flow_enabled\":false,\"enable_code_embed_toc\":false,\"enable_publication_tax_settings\":false,\"gifts_from_substack_feature_available\":true,\"disable_ai_clips\":false,\"enable_elevenlabs_voiceovers\":false,\"thefp_enable_transcripts\":false,\"show_simple_post_editor\":false,\"instacart_integration_enabled\":false,\"enable_publication_podcasts_page\":false,\"enable_direct_message_request_bypass\":false,\"enable_apple_news_sync\":false,\"live_stream_in_trending_topic_overrides\":\"\",\"free_press_newsletter_promo_enabled\":false,\"account_based_post_metering_enabled\":false,\"disable_live_stream_reactions\":false,\"instacart_partner_id\":\"\",\"enable_adhoc_email_scheduling\":true,\"media_feed_prepend_inbox_limit\":35,\"welcome_page_no_opt_out\":false,\"enable_caption_translation_tools\":false,\"section_specific_postscripts\":false,\"edit_profile_theme_colors\":false,\"disable_clipping_for_readers\":false,\"enable_apple_podcast_delivery_self_serve_pem_files\":false,\"enable_press_kit_preview_modal\":false,\"enable_rnc_page\":true,\"live_stream_video_degradation_preference\":\"maintainFramerate\",\"enable_high_follower_dm\":true,\"pause_app_badges\":false,\"profile_feed_expanded_inventory\":false,\"livekit_mux_latency_mode\":\"low\",\"feed_juiced_user\":0,\"global_iap_plan_setup_countries\":\"AE,AG,AL,AM,AT,AU,BA,BG,BH,BJ,BN,BS,BT,BW,CH,CI,CR,CY,CZ,DK,DZ,EC,EE,ET,FI,GM,GT,GY,HK,HR,HU,ID,IL,IN,IS,JM,JO,KE,KW,LC,LI,LK,LT,LU,LV,MA,MD,MG,MK,MN,MT,MU,MX,MY,MZ,NA,NO,NZ,OM,PA,PE,PH,PK,QA,RO,RS,RW,SE,SG,SI,SK,SN,SV,TH,TN,TR,TT,TW,TZ,UZ,VN,ZA\",\"enable_collapsed_content\":false,\"enable_polymarket_expandable_embeds\":true,\"publisher_dashboard_group_subs_sidebar\":false,\"use_advanced_commerce_api_for_iap\":false,\"skip_free_preview_language_in_podcast_notes\":false,\"larger_wordmark_on_publication_homepage\":false,\"enable_mobile_stats_for_admins\":false,\"enable_livestream_youtube_simulcast\":false,\"enable_persona_sandbox_environment\":false,\"allowed_email_domains\":\"mozmail.com\",\"create_nav_item_from_tag\":false,\"bypass_single_unlock_token_limit\":false,\"enable_code_embeds\":false,\"add_section_and_tag_metadata\":false,\"daily_promoted_notes_enabled\":true,\"enable_segments_ui_revamp\":true,\"enable_islands_cms\":false,\"enable_livestream_combined_stats\":false,\"redirect_to_pub_after_welcome_signup\":false,\"chartbeat_video_enabled\":false,\"enable_drip_campaigns\":false,\"enable_filtered_posts_on_homepage\":false,\"post_management_search_engine\":\"elasticsearch\",\"new_bestseller_leaderboard_feed_item_enabled\":false,\"feed_main_disabled\":false,\"enable_account_settings_revamp\":false,\"thefp_enable_fp_recirc_block\":false,\"top_search_variant\":\"control\",\"enable_debug_logs_ios\":false,\"show_pub_content_on_profile_for_pub_id\":0,\"show_pub_content_on_profile\":false,\"livekit_track_egress\":true,\"onboarding_suggestions_search\":\"experiment\",\"feed_tuner_enabled\":false,\"livekit_mux_latency_mode_rtmp\":\"low\",\"google_login_enabled\":false,\"livekit_high_quality_egress\":false,\"iap_announcement_blog_url\":\"\",\"disable_code_embed_chrome\":false,\"ios_livestream_feedback\":false,\"founding_plan_upgrade_warning\":false,\"ios_mediaplayer_reply_bar_v2\":false,\"enable_notification_email_batching\":true,\"note_author_poll_results_visible_by_default\":true,\"ios_hide_portal_tab_bar\":false,\"follow_upsell_rollout_percentage\":30,\"gift_article_enabled\":false,\"live_stream_invite_ttl_seconds\":900000,\"include_founding_plans_coupon_option\":false,\"thefp_enable_cancellation_discount_offer\":false,\"android_enable_edit_profile_theme\":false,\"disable_audio_enhancement\":false,\"pub_search_variant\":\"control\",\"ignore_video_in_notes_length_limit\":false,\"substack_gtm_enabled\":false,\"allow_long_videos\":true,\"enable_automation_filters\":false,\"use_enhanced_video_embed_player\":true,\"founding_upgrade_preview\":false,\"enable_viewing_all_livestream_viewers\":false,\"send_subscription_canceled_email\":false,\"enable_clip_prompt_variant_filtering\":true,\"chartbeat_enabled\":false,\"dpn_ranking_enabled\":true,\"enable_custom_email_css\":false,\"thefp_enable_shows_page\":false,\"enable_apple_podcast_auto_publish\":false,\"linkedin_profile_search_enabled\":false,\"publication_has_own_app\":false,\"suggested_minimum_ios_version\":0,\"thebulwark_enable_footer_actions\":false,\"enable_posts_to_segments\":true,\"trending_topics_module_long_term_experiment\":\"control\",\"phone_verification_fallback_to_twilio\":false,\"enable_suggested_searches\":true,\"enable_subscription_notification_email_batching\":true,\"feed_controls\":\"control\",\"thefp_enable_plans_modal_v2\":false,\"a24_redemption_link\":\"\",\"design_templates_launch_phase\":\"off\",\"post_custom_email_from_name_enabled\":false,\"ios_live_stream_auto_gain_enabled\":true,\"enable_publication_tts_player\":false,\"enable_group_direct_messages\":true,\"enable_notes_admins\":false,\"thefp_show_pub_app_callout_on_post\":false,\"search_ranker_variant\":\"experiment\",\"forced_featured_topic_id\":\"\",\"ios_audio_captions_disabled\":false,\"web_podcasts_tab\":false,\"related_posts_enabled\":false,\"thefp_enable_homepage_secondary_nav\":false,\"ios_live_stream_pip_dismiss_v4\":\"control\",\"reply_rate_limit_max_distinct_users_daily\":110,\"web_post_metering_enabled\":true,\"search_retrieval_variant\":\"experiment\",\"mobile_user_attachments_enabled\":false,\"web_profile_publication_recommendations_carousel\":true,\"publisher_banner\":\"\",\"enable_sponsorship_profile\":false,\"gift_article_button_enabled\":false,\"reply_rate_limit_max_distinct_users_monthly\":600,\"desktop_live_stream_screen_share_audio_enabled\":false,\"creator_match\":true,\"ai_image_generation_enabled\":true,\"ios_default_coupon_enabled\":true,\"automod_admin_hidden_comments_tab\":true,\"video_clip_suggestions_enabled\":false,\"publisher_dashboard_home_layout_experiment\":\"control\",\"android_polymarket_embed_search\":false,\"audience_section_editor_help_link\":\"https://support.substack.com/hc/en-us/articles/50558240901268-How-do-I-add-audience-specific-content-to-a-post-on-Substack\",\"portal_ranking_variant\":\"experiment\",\"permalink_reply_ranking_variant\":\"experiment\",\"allow_feed_category_filtering\":false,\"enable_dynamic_content\":true,\"enable_thumbnail_editor_media_settings_integration\":false,\"subscriber_profile_survey_responses_enabled\":true,\"private_live_streaming_enabled\":true,\"desktop_live_stream_safe_framing\":0.8,\"translate_posts_on_standalone_sites\":true,\"bundle_subscribe_default_to_regular_plan\":false,\"enable_standardized_sponsorship_formats\":false,\"enable_pencraft_signin_form\":true,\"thefp_enable_secondary_section_redesign\":false,\"bignight_page_enabled\":true,\"thefp_paywall_annual_plans_experiment\":\"control\",\"enable_launch_assistant\":false,\"enable_youtube_exploration\":true,\"publisher_dashboard_nav_refresh\":false,\"thefp_enable_bundle_post_follow\":false,\"web_notes_tiptap_v3_experiment\":\"treatment_tiptap_v3\",\"recipe_rich_text_enabled\":true,\"publisher_dashboard_nav_refresh_experiment\":\"treatment\",\"chat_channel_creation_enabled\":false,\"web_onboarding_content_type_preferences\":\"experiment\",\"web_mobile_asset_handoff\":false},\"trackingTokens\":{\"fbPixelId\":null,\"gaPixelId\":null,\"twitterPixelId\":null,\"parselyPixelId\":null,\"googleTagManagerToken\":\"\",\"googleAnalytics4Token\":\"G-G8RXW18CW7\",\"twitterPixelSignupEventId\":null,\"twitterPixelSubscribeEventId\":null},\"publicationSettings\":{\"block_ai_crawlers\":false,\"credit_token_enabled\":true,\"custom_tos_and_privacy\":false,\"did_identity\":null,\"disable_optimistic_bank_payments\":false,\"display_welcome_page_details\":true,\"payment_pledges_enabled\":false,\"enable_drop_caps\":false,\"enable_post_page_conversion\":true,\"enable_prev_next_nav\":false,\"enable_restacking\":false,\"founding_group_subscriptions_enabled\":false,\"gifts_from_substack_disabled\":false,\"google_analytics_4_token\":\"G-G8RXW18CW7\",\"group_sections_and_podcasts_in_menu_enabled\":false,\"live_stream_homepage_visibility\":\"contributorsAndAdmins\",\"live_stream_homepage_style\":\"autoPlay\",\"live_stream_replay_enabled\":true,\"medium_length_description\":\"Senior Staff Engineer distilling 2+ decades of experience in System Reliability Engineering, Technical Leadership, and growth\",\"notes_feed_enabled\":true,\"paywall_unlock_tokens\":true,\"post_preview_crop_gravity\":\"center\",\"post_preview_radius\":\"xs\",\"reader_referrals_enabled\":true,\"reader_referrals_leaderboard_enabled\":true,\"seen_coming_soon_explainer\":false,\"seen_google_analytics_migration_modal\":false,\"local_currency_modal_seen\":true,\"local_payment_methods_modal_seen\":true,\"twitter_pixel_signup_event_id\":null,\"twitter_pixel_subscribe_event_id\":null,\"use_inclusive_sales_tax\":false,\"use_local_currency\":true,\"welcome_page_opt_out_text\":\"Maybe Later\",\"cookie_settings\":\"\",\"show_restacks_below_posts\":true,\"holiday_gifting_post_header\":true,\"homepage_message_text\":\"\",\"homepage_message_link\":\"\",\"about_us_author_ids\":\"\",\"archived_section_ids\":\"\",\"column_section_ids\":\"\",\"fp_primary_column_section_ids\":\"\",\"event_section_ids\":\"\",\"podcasts_metadata\":\"\",\"video_section_ids\":\"\",\"post_metering_enabled\":false,\"account_based_post_metering_enabled\":false,\"use_custom_theme\":false,\"reply_rules\":null,\"automatic_moderation_enabled\":true,\"auto_translate_enabled\":true,\"additional_post_languages_enabled\":false,\"high_res_recording_beta\":false},\"publicationUserSettings\":null,\"userSettings\":{\"user_id\":null,\"activity_likes_enabled\":true,\"dashboard_nav_refresh_enabled\":false,\"is_guest_post_enabled\":true,\"invite_friends_nux_dismissed_at\":null,\"suggestions_feed_item_last_shown_at\":null,\"last_notification_alert_shown_at\":null,\"disable_reply_hiding\":false,\"newest_seen_chat_item_published_at\":null,\"explicitContentEnabled\":false,\"contactMatchingEnabled\":false,\"messageRequestLevel\":\"everyone\",\"liveStreamAcceptableInviteLevel\":\"everyone\",\"liveStreamAcceptableChatLevel\":\"everyone\",\"creditTokensTreatmentExposed\":false,\"appBadgeIncludesChat\":false,\"autoPlayVideo\":true,\"autoAdvanceVideo\":true,\"smart_delivery_enabled\":false,\"chatbotTermsLastAcceptedAt\":null,\"has_seen_notes_post_app_upsell\":false,\"first_note_id\":null,\"show_concurrent_live_stream_viewers\":false,\"edit_profile_feed_item_dismissed_at\":null,\"mobile_permalink_app_upsell_seen_at\":null,\"new_user_checklist_enabled\":false,\"has_seen_youtube_shorts_auto_publish_announcement\":false,\"has_seen_publish_youtube_connect_upsell\":false,\"notificationQualityFilterEnabled\":true,\"hasSeenOnboardingNewslettersScreen\":false,\"bestsellerBadgeEnabled\":true,\"hasSelfIdentifiedAsCreator\":false,\"autoTranslateEnabled\":true,\"autoTranslateBlocklist\":[],\"fineTuneFeedItemSeenAt\":null,\"fineTuneFeedItemDismissedAt\":null,\"aiGeneratedTextMode\":\"show\",\"feedVideoPreference\":5,\"feedAudioPreference\":5,\"feedLongerPostsPreference\":5,\"feedChatPreference\":5},\"mux_env_key\":\"u42pci814i6011qg3segrcpp9\",\"persona_environment_id\":\"env_o1Lbk4JhpY4PmvNkwaBdYwe5Fzkt\",\"sentry_environment\":\"production\",\"launchWelcomePage\":false,\"pendingInviteForActiveLiveStream\":null,\"isEligibleForLiveStreamCreation\":true,\"webviewPlatform\":null,\"noIndex\":false,\"post\":{\"audience\":\"only_paid\",\"audience_before_archived\":null,\"canonical_url\":\"https://blog.alexewerlof.com/p/slo\",\"default_comment_sort\":null,\"editor_v2\":false,\"exempt_from_archive_paywall\":false,\"free_unlock_required\":false,\"id\":142248697,\"podcast_art_url\":null,\"podcast_duration\":null,\"podcast_preview_upload_id\":null,\"podcast_upload_id\":null,\"podcast_url\":null,\"post_date\":\"2024-05-06T12:45:03.587Z\",\"updated_at\":\"2025-06-19T12:41:10.515Z\",\"publication_id\":1002265,\"search_engine_description\":\"Dive into the fundamentals of Service Level Objectives (SLOs) with this guide. Understand SLOs, error budgets, and their practical implications through real-world examples. Learn to set and manage SLOs effectively with case studies on API service reliability.\",\"search_engine_title\":null,\"section_id\":67723,\"should_send_free_preview\":true,\"show_guest_bios\":true,\"slug\":\"slo\",\"social_title\":\"SLO\",\"subtitle\":\"Introduction to Service Level Objectives and their relationship with error budgets\",\"teaser_post_eligible\":true,\"title\":\"SLO\",\"type\":\"newsletter\",\"video_upload_id\":null,\"write_comment_permissions\":\"everyone\",\"meter_type\":\"none\",\"live_stream_id\":null,\"is_published\":true,\"restacks\":3,\"reactions\":{\"\u2764\":19},\"top_exclusions\":[],\"pins\":[],\"section_pins\":[],\"has_shareable_clips\":false,\"previous_post_slug\":\"nfr\",\"next_post_slug\":\"service\",\"cover_image\":\"https://substackcdn.com/image/fetch/f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F0ec62079-bcea-47fa-aafc-e3f7b6ed0f9a_1054x876.png\",\"cover_image_is_square\":false,\"cover_image_is_explicit\":false,\"videoUpload\":null,\"podcastFields\":{\"post_id\":142248697,\"podcast_episode_number\":null,\"podcast_season_number\":null,\"podcast_episode_type\":null,\"should_syndicate_to_other_feed\":null,\"syndicate_to_section_id\":null,\"hide_from_feed\":false,\"free_podcast_url\":null,\"free_podcast_duration\":null,\"preview_contains_ad\":false,\"was_imported_self_serve_sync\":false,\"draft_free_podcast_url\":null,\"draft_free_podcast_duration\":null},\"podcastUpload\":null,\"podcastPreviewUpload\":null,\"voiceover_upload_id\":null,\"voiceoverUpload\":null,\"has_voiceover\":false,\"description\":\"Introduction to Service Level Objectives and their relationship with error budgets\",\"body_html\":\"<p>Service Level Objective (SLO) sets the reliability expectation for the service based on how the service consumer perceives reliability (<a href=\\\"https://blog.alexewerlof.com/p/sli\\\">SLI</a>).</p><p>One of the key ideas behind SLO is to shift the expectations from 100% reliability (which is not practical, and leads to disappointment, finger-pointing, and unreasonably high cost) to a number that is reasonable (e.g. 99%).</p><p>The difference is small (e.g. 1%) but it clarifies the error budget as a way to transparently balance the cost of reliability while controlling the risks of changing a system and setting the pace of those changes. The \u201Cpace\u201D aspect comes in handy when doing <a href=\\\"https://blog.alexewerlof.com/p/wardley-maps-and-pace-layering-for\\\">Pace Layering</a>, for example the critical services have a stricter reliability goal than the more experimental ones.</p><p>SLOs are internal <strong>goals</strong> that help teams make data-driven decisions about reliability and prioritize engineering work, such as balancing the speed of feature delivery with the need for stability </p><div class=\\\"captioned-image-container\\\"><figure><a class=\\\"image-link image2 is-viewable-img\\\" target=\\\"_blank\\\" href=\\\"https://substackcdn.com/image/fetch/$s_!z_xD!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F2d3d3162-72c1-4b39-927a-a0a121508054_1033x1026.png\\\" data-component-name=\\\"Image2ToDOM\\\"><div class=\\\"image2-inset\\\"><picture><source type=\\\"image/webp\\\" srcset=\\\"https://substackcdn.com/image/fetch/$s_!z_xD!,w_424,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F2d3d3162-72c1-4b39-927a-a0a121508054_1033x1026.png 424w, https://substackcdn.com/image/fetch/$s_!z_xD!,w_848,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F2d3d3162-72c1-4b39-927a-a0a121508054_1033x1026.png 848w, https://substackcdn.com/image/fetch/$s_!z_xD!,w_1272,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F2d3d3162-72c1-4b39-927a-a0a121508054_1033x1026.png 1272w, https://substackcdn.com/image/fetch/$s_!z_xD!,w_1456,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F2d3d3162-72c1-4b39-927a-a0a121508054_1033x1026.png 1456w\\\" sizes=\\\"100vw\\\"><img src=\\\"https://substackcdn.com/image/fetch/$s_!z_xD!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F2d3d3162-72c1-4b39-927a-a0a121508054_1033x1026.png\\\" width=\\\"1033\\\" height=\\\"1026\\\" data-attrs=\\\"{&quot;src&quot;:&quot;https://substack-post-media.s3.amazonaws.com/public/images/2d3d3162-72c1-4b39-927a-a0a121508054_1033x1026.png&quot;,&quot;srcNoWatermark&quot;:null,&quot;fullscreen&quot;:null,&quot;imageSize&quot;:null,&quot;height&quot;:1026,&quot;width&quot;:1033,&quot;resizeWidth&quot;:null,&quot;bytes&quot;:159959,&quot;alt&quot;:null,&quot;title&quot;:null,&quot;type&quot;:&quot;image/png&quot;,&quot;href&quot;:null,&quot;belowTheFold&quot;:false,&quot;topImage&quot;:true,&quot;internalRedirect&quot;:null,&quot;isProcessing&quot;:false,&quot;align&quot;:null,&quot;offset&quot;:false}\\\" class=\\\"sizing-normal\\\" alt=\\\"\\\" srcset=\\\"https://substackcdn.com/image/fetch/$s_!z_xD!,w_424,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F2d3d3162-72c1-4b39-927a-a0a121508054_1033x1026.png 424w, https://substackcdn.com/image/fetch/$s_!z_xD!,w_848,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F2d3d3162-72c1-4b39-927a-a0a121508054_1033x1026.png 848w, https://substackcdn.com/image/fetch/$s_!z_xD!,w_1272,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F2d3d3162-72c1-4b39-927a-a0a121508054_1033x1026.png 1272w, https://substackcdn.com/image/fetch/$s_!z_xD!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F2d3d3162-72c1-4b39-927a-a0a121508054_1033x1026.png 1456w\\\" sizes=\\\"100vw\\\" fetchpriority=\\\"high\\\"></picture><div class=\\\"image-link-expand\\\"><div class=\\\"pencraft pc-display-flex pc-gap-8 pc-reset\\\"><button tabindex=\\\"0\\\" type=\\\"button\\\" class=\\\"pencraft pc-reset pencraft icon-container restack-image\\\"><svg aria-hidden=\\\"true\\\" width=\\\"20\\\" height=\\\"20\\\" viewBox=\\\"0 0 20 20\\\" fill=\\\"none\\\" stroke-width=\\\"1.5\\\" stroke=\\\"var(--color-fg-primary)\\\" stroke-linecap=\\\"round\\\" stroke-linejoin=\\\"round\\\" xmlns=\\\"http://www.w3.org/2000/svg\\\"><g><path d=\\\"M2.53001 7.81595C3.49179 4.73911 6.43281 2.5 9.91173 2.5C13.1684 2.5 15.9537 4.46214 17.0852 7.23684L17.6179 8.67647M17.6179 8.67647L18.5002 4.26471M17.6179 8.67647L13.6473 6.91176M17.4995 12.1841C16.5378 15.2609 13.5967 17.5 10.1178 17.5C6.86118 17.5 4.07589 15.5379 2.94432 12.7632L2.41165 11.3235M2.41165 11.3235L1.5293 15.7353M2.41165 11.3235L6.38224 13.0882\\\"></path></g></svg></button><button tabindex=\\\"0\\\" type=\\\"button\\\" class=\\\"pencraft pc-reset pencraft icon-container view-image\\\"><svg xmlns=\\\"http://www.w3.org/2000/svg\\\" width=\\\"20\\\" height=\\\"20\\\" viewBox=\\\"0 0 24 24\\\" fill=\\\"none\\\" stroke=\\\"currentColor\\\" stroke-width=\\\"2\\\" stroke-linecap=\\\"round\\\" stroke-linejoin=\\\"round\\\" class=\\\"lucide lucide-maximize2 lucide-maximize-2\\\"><polyline points=\\\"15 3 21 3 21 9\\\"></polyline><polyline points=\\\"9 21 3 21 3 15\\\"></polyline><line x1=\\\"21\\\" x2=\\\"14\\\" y1=\\\"3\\\" y2=\\\"10\\\"></line><line x1=\\\"3\\\" x2=\\\"10\\\" y1=\\\"21\\\" y2=\\\"14\\\"></line></svg></button></div></div></div></a></figure></div><p>There are three aspects that defining a SLO:</p><ol><li><p><strong>The value:</strong> usually a number like <code>99.9%</code></p></li><li><p><strong><a href=\\\"https://blog.alexewerlof.com/p/compliance-period\\\">The compliance period</a> (also known as \u201Cwindow\u201D):</strong> usually <code>30</code> days. This is the time window which is used to count events or time-slices in the past to calculate the SLS (<a href=\\\"https://blog.alexewerlof.com/p/sls\\\">Service Level Status</a>).</p></li><li><p><strong><a href=\\\"https://blog.alexewerlof.com/p/sli-good\\\">The boundaries</a> (optional):</strong> for SLIs that use thresholds for what good events look like (e.g., if a latency below <code>800ms</code> is considered good, the number 800ms is part of the threshold).</p></li></ol><p><em>Note: all three are used for <a href=\\\"https://blog.alexewerlof.com/p/multi-tiered-slos\\\">multi-tiered SLOs</a> which tie to the same SLI.</em></p><p>SLO heavily impacts the non-functional requirements (<a href=\\\"https://blog.alexewerlof.com/p/nfr\\\">NFR</a>) for how the technical solution is designed, built, operated, secured, maintained, and budgeted.</p><p>While SLO gets all the publicity, the <a href=\\\"https://blog.alexewerlof.com/p/error-budget\\\">error budget</a> is the real hero of reliability engineering. If you remember from <a href=\\\"https://blog.alexewerlof.com/p/why-bother-with-sli-and-slo\\\">why bother with service levels</a>, we are trying to shift the mindset from \u201Csystems should never fail\u201D to understanding what failure is (SLI) and how much of it can be tolerated (error budget).</p><div class=\\\"captioned-image-container\\\"><figure><a class=\\\"image-link image2 is-viewable-img\\\" target=\\\"_blank\\\" href=\\\"https://substackcdn.com/image/fetch/$s_!gF3S!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Faf604aef-6dca-4aee-8084-18d73ad061de_559x447.jpeg\\\" data-component-name=\\\"Image2ToDOM\\\"><div class=\\\"image2-inset\\\"><picture><source type=\\\"image/webp\\\" srcset=\\\"https://substackcdn.com/image/fetch/$s_!gF3S!,w_424,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Faf604aef-6dca-4aee-8084-18d73ad061de_559x447.jpeg 424w, https://substackcdn.com/image/fetch/$s_!gF3S!,w_848,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Faf604aef-6dca-4aee-8084-18d73ad061de_559x447.jpeg 848w, https://substackcdn.com/image/fetch/$s_!gF3S!,w_1272,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Faf604aef-6dca-4aee-8084-18d73ad061de_559x447.jpeg 1272w, https://substackcdn.com/image/fetch/$s_!gF3S!,w_1456,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Faf604aef-6dca-4aee-8084-18d73ad061de_559x447.jpeg 1456w\\\" sizes=\\\"100vw\\\"><img src=\\\"https://substackcdn.com/image/fetch/$s_!gF3S!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Faf604aef-6dca-4aee-8084-18d73ad061de_559x447.jpeg\\\" width=\\\"559\\\" height=\\\"447\\\" data-attrs=\\\"{&quot;src&quot;:&quot;https://substack-post-media.s3.amazonaws.com/public/images/af604aef-6dca-4aee-8084-18d73ad061de_559x447.jpeg&quot;,&quot;srcNoWatermark&quot;:null,&quot;fullscreen&quot;:null,&quot;imageSize&quot;:null,&quot;height&quot;:447,&quot;width&quot;:559,&quot;resizeWidth&quot;:null,&quot;bytes&quot;:null,&quot;alt&quot;:null,&quot;title&quot;:null,&quot;type&quot;:null,&quot;href&quot;:null,&quot;belowTheFold&quot;:true,&quot;topImage&quot;:false,&quot;internalRedirect&quot;:null,&quot;isProcessing&quot;:false,&quot;align&quot;:null,&quot;offset&quot;:false}\\\" class=\\\"sizing-normal\\\" alt=\\\"\\\" srcset=\\\"https://substackcdn.com/image/fetch/$s_!gF3S!,w_424,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Faf604aef-6dca-4aee-8084-18d73ad061de_559x447.jpeg 424w, https://substackcdn.com/image/fetch/$s_!gF3S!,w_848,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Faf604aef-6dca-4aee-8084-18d73ad061de_559x447.jpeg 848w, https://substackcdn.com/image/fetch/$s_!gF3S!,w_1272,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Faf604aef-6dca-4aee-8084-18d73ad061de_559x447.jpeg 1272w, https://substackcdn.com/image/fetch/$s_!gF3S!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Faf604aef-6dca-4aee-8084-18d73ad061de_559x447.jpeg 1456w\\\" sizes=\\\"100vw\\\" loading=\\\"lazy\\\"></picture><div class=\\\"image-link-expand\\\"><div class=\\\"pencraft pc-display-flex pc-gap-8 pc-reset\\\"><button tabindex=\\\"0\\\" type=\\\"button\\\" class=\\\"pencraft pc-reset pencraft icon-container restack-image\\\"><svg aria-hidden=\\\"true\\\" width=\\\"20\\\" height=\\\"20\\\" viewBox=\\\"0 0 20 20\\\" fill=\\\"none\\\" stroke-width=\\\"1.5\\\" stroke=\\\"var(--color-fg-primary)\\\" stroke-linecap=\\\"round\\\" stroke-linejoin=\\\"round\\\" xmlns=\\\"http://www.w3.org/2000/svg\\\"><g><path d=\\\"M2.53001 7.81595C3.49179 4.73911 6.43281 2.5 9.91173 2.5C13.1684 2.5 15.9537 4.46214 17.0852 7.23684L17.6179 8.67647M17.6179 8.67647L18.5002 4.26471M17.6179 8.67647L13.6473 6.91176M17.4995 12.1841C16.5378 15.2609 13.5967 17.5 10.1178 17.5C6.86118 17.5 4.07589 15.5379 2.94432 12.7632L2.41165 11.3235M2.41165 11.3235L1.5293 15.7353M2.41165 11.3235L6.38224 13.0882\\\"></path></g></svg></button><button tabindex=\\\"0\\\" type=\\\"button\\\" class=\\\"pencraft pc-reset pencraft icon-container view-image\\\"><svg xmlns=\\\"http://www.w3.org/2000/svg\\\" width=\\\"20\\\" height=\\\"20\\\" viewBox=\\\"0 0 24 24\\\" fill=\\\"none\\\" stroke=\\\"currentColor\\\" stroke-width=\\\"2\\\" stroke-linecap=\\\"round\\\" stroke-linejoin=\\\"round\\\" class=\\\"lucide lucide-maximize2 lucide-maximize-2\\\"><polyline points=\\\"15 3 21 3 21 9\\\"></polyline><polyline points=\\\"9 21 3 21 3 15\\\"></polyline><line x1=\\\"21\\\" x2=\\\"14\\\" y1=\\\"3\\\" y2=\\\"10\\\"></line><line x1=\\\"3\\\" x2=\\\"10\\\" y1=\\\"21\\\" y2=\\\"14\\\"></line></svg></button></div></div></div></a></figure></div><p>Error budget is the maximum percentage of failure that the service is allowed to have in a given period. It is directly tied to the SLO. In fact, it complements the SLO:</p><div class=\\\"latex-rendered\\\" data-attrs=\\\"{&quot;persistentExpression&quot;:&quot;Error Budget = 100 - SLO&quot;,&quot;id&quot;:&quot;UPLUUWSECW&quot;}\\\" data-component-name=\\\"LatexBlockToDOM\\\"></div><p>For example, if the SLO is <code>99%</code>, the <em>error budget</em> is <code>1%</code>. If SLO is <code>99.6%</code>, the <em>error budget</em> is <code>0.4%</code>.</p><h2>Example</h2><p>Let\u2019s start simple by defining an SLO for an API (service) which is consumed by two teams: a mobile team and a web team (service consumers).</p><p>The mobile app and web are the interface towards users. The business makes money by charging the users a monthly fee (e.g., something like Netflix).</p><p><em>Note: since money is involved, there may be an <a href=\\\"https://blog.alexewerlof.com/p/sla\\\">SLA</a> too, but it\u2019s out of the scope of this article.</em></p><div class=\\\"captioned-image-container\\\"><figure><a class=\\\"image-link image2 is-viewable-img\\\" target=\\\"_blank\\\" href=\\\"https://substackcdn.com/image/fetch/$s_!43pu!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F727459b6-ec69-4604-b92d-b2149780fce1_969x745.png\\\" data-component-name=\\\"Image2ToDOM\\\"><div class=\\\"image2-inset\\\"><picture><source type=\\\"image/webp\\\" srcset=\\\"https://substackcdn.com/image/fetch/$s_!43pu!,w_424,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F727459b6-ec69-4604-b92d-b2149780fce1_969x745.png 424w, https://substackcdn.com/image/fetch/$s_!43pu!,w_848,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F727459b6-ec69-4604-b92d-b2149780fce1_969x745.png 848w, https://substackcdn.com/image/fetch/$s_!43pu!,w_1272,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F727459b6-ec69-4604-b92d-b2149780fce1_969x745.png 1272w, https://substackcdn.com/image/fetch/$s_!43pu!,w_1456,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F727459b6-ec69-4604-b92d-b2149780fce1_969x745.png 1456w\\\" sizes=\\\"100vw\\\"><img src=\\\"https://substackcdn.com/image/fetch/$s_!43pu!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F727459b6-ec69-4604-b92d-b2149780fce1_969x745.png\\\" width=\\\"969\\\" height=\\\"745\\\" data-attrs=\\\"{&quot;src&quot;:&quot;https://substack-post-media.s3.amazonaws.com/public/images/727459b6-ec69-4604-b92d-b2149780fce1_969x745.png&quot;,&quot;srcNoWatermark&quot;:null,&quot;fullscreen&quot;:null,&quot;imageSize&quot;:null,&quot;height&quot;:745,&quot;width&quot;:969,&quot;resizeWidth&quot;:null,&quot;bytes&quot;:80576,&quot;alt&quot;:null,&quot;title&quot;:null,&quot;type&quot;:&quot;image/png&quot;,&quot;href&quot;:null,&quot;belowTheFold&quot;:true,&quot;topImage&quot;:false,&quot;internalRedirect&quot;:null,&quot;isProcessing&quot;:false,&quot;align&quot;:null,&quot;offset&quot;:false}\\\" class=\\\"sizing-normal\\\" alt=\\\"\\\" srcset=\\\"https://substackcdn.com/image/fetch/$s_!43pu!,w_424,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F727459b6-ec69-4604-b92d-b2149780fce1_969x745.png 424w, https://substackcdn.com/image/fetch/$s_!43pu!,w_848,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F727459b6-ec69-4604-b92d-b2149780fce1_969x745.png 848w, https://substackcdn.com/image/fetch/$s_!43pu!,w_1272,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F727459b6-ec69-4604-b92d-b2149780fce1_969x745.png 1272w, https://substackcdn.com/image/fetch/$s_!43pu!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F727459b6-ec69-4604-b92d-b2149780fce1_969x745.png 1456w\\\" sizes=\\\"100vw\\\" loading=\\\"lazy\\\"></picture><div class=\\\"image-link-expand\\\"><div class=\\\"pencraft pc-display-flex pc-gap-8 pc-reset\\\"><button tabindex=\\\"0\\\" type=\\\"button\\\" class=\\\"pencraft pc-reset pencraft icon-container restack-image\\\"><svg aria-hidden=\\\"true\\\" width=\\\"20\\\" height=\\\"20\\\" viewBox=\\\"0 0 20 20\\\" fill=\\\"none\\\" stroke-width=\\\"1.5\\\" stroke=\\\"var(--color-fg-primary)\\\" stroke-linecap=\\\"round\\\" stroke-linejoin=\\\"round\\\" xmlns=\\\"http://www.w3.org/2000/svg\\\"><g><path d=\\\"M2.53001 7.81595C3.49179 4.73911 6.43281 2.5 9.91173 2.5C13.1684 2.5 15.9537 4.46214 17.0852 7.23684L17.6179 8.67647M17.6179 8.67647L18.5002 4.26471M17.6179 8.67647L13.6473 6.91176M17.4995 12.1841C16.5378 15.2609 13.5967 17.5 10.1178 17.5C6.86118 17.5 4.07589 15.5379 2.94432 12.7632L2.41165 11.3235M2.41165 11.3235L1.5293 15.7353M2.41165 11.3235L6.38224 13.0882\\\"></path></g></svg></button><button tabindex=\\\"0\\\" type=\\\"button\\\" class=\\\"pencraft pc-reset pencraft icon-container view-image\\\"><svg xmlns=\\\"http://www.w3.org/2000/svg\\\" width=\\\"20\\\" height=\\\"20\\\" viewBox=\\\"0 0 24 24\\\" fill=\\\"none\\\" stroke=\\\"currentColor\\\" stroke-width=\\\"2\\\" stroke-linecap=\\\"round\\\" stroke-linejoin=\\\"round\\\" class=\\\"lucide lucide-maximize2 lucide-maximize-2\\\"><polyline points=\\\"15 3 21 3 21 9\\\"></polyline><polyline points=\\\"9 21 3 21 3 15\\\"></polyline><line x1=\\\"21\\\" x2=\\\"14\\\" y1=\\\"3\\\" y2=\\\"10\\\"></line><line x1=\\\"3\\\" x2=\\\"10\\\" y1=\\\"21\\\" y2=\\\"14\\\"></line></svg></button></div></div></div></a></figure></div><p>The mobile and web team want to hold the team behind the API (service provider) accountable for keeping the API available.</p><p>The service consumers in this example perceive the reliability of the API based on its uptime (i.e., a <a href=\\\"https://blog.alexewerlof.com/p/time-based-vs-event-based\\\">time-based SLI</a>).</p><p>Together with the API team they agree to use a probe to check the API availability every minute </p><p><em>Note: there are many ways to measure availability. Pinging an end point every minute doesn\u2019t give the best signal but it\u2019s easy to start with.</em></p><p>They decided on an SLO window of <code>30 days</code> because the subscribers are charged on a monthly basis and the UX study has some data about how much failure the customers can put up with before they seriously consider cancelling their subscription.</p><p>The maximum downtime the web team can tolerate is <code>10 minutes</code> per month.</p><p>But the mobile app team can tolerate a maximum of <code>2 hours</code> downtime per month due to on-device caching in their implementation.</p><p>Here\u2019s what we know:</p><ul><li><p><strong>Service</strong> = API</p></li><li><p><strong>Service Provider</strong> = the team behind the API</p></li><li><p><strong>Service Consumers</strong> = mobile app and web team</p></li><li><p><strong><a href=\\\"https://blog.alexewerlof.com/p/sli\\\">Service Level Indicator</a></strong> = Availability. Ping the <code>/health</code> endpoint every minute (<a href=\\\"https://blog.alexewerlof.com/p/time-based-vs-event-based\\\">time-based</a>)</p><ul><li><p><strong><a href=\\\"https://blog.alexewerlof.com/p/sli-good\\\">Good</a></strong> = the number of probes that returns <code>HTTP 200</code></p></li><li><p><strong><a href=\\\"https://blog.alexewerlof.com/p/valid-vs-total\\\">Valid</a></strong> = the number of probes sent during the compliance period</p></li></ul></li><li><p><strong><a href=\\\"https://blog.alexewerlof.com/p/compliance-period\\\">Compliance Period</a></strong><a href=\\\"https://blog.alexewerlof.com/p/compliance-period\\\"> (SLO window)</a> = <code>30 days</code> = <code>43800 minutes</code> (you can <a href=\\\"https://www.google.com/search?q=month+to+minutes\\\">use Google</a> for these conversions)</p><ul><li><p>Rolling window: at any given time, we look at the past <code>43800 minutes</code>.</p></li></ul></li><li><p><strong><a href=\\\"https://blog.alexewerlof.com/p/error-budget\\\">Error budget</a></strong> = <code>min(10m, 120m)</code> (the SLO needs to satisfy the requirement of the most demanding consumer.</p></li></ul><p>The API team checks the historical data for their availability metrics. We call that a <a href=\\\"https://blog.alexewerlof.com/p/sls\\\">Service Level Status</a> (SLS) to distinguish it from the SLI which is a metric and SLO which is an objective.</p><p>The API team checked their historical uptime and learned that in the past <code>90 days (129600 minutes)</code>, they had a downtime of <code>85 minutes</code>. That\u2019s what they\u2019re comfortable to commit to (the status-quo):</p><div class=\\\"latex-rendered\\\" data-attrs=\\\"{&quot;persistentExpression&quot;:&quot;SLS_{90d} = \\\\\\\\frac { 129600-85 }{129600} \\\\\\\\times 100 = 99.93\\\\\\\\%&quot;,&quot;id&quot;:&quot;VDNNNTRDBL&quot;}\\\" data-component-name=\\\"LatexBlockToDOM\\\"></div><p>This is below the level that the web team can tolerate (10 minutes downtime in 30 days):</p><div class=\\\"latex-rendered\\\" data-attrs=\\\"{&quot;persistentExpression&quot;:&quot;SLO_{web} = \\\\\\\\frac { 43800-10 }{43800} \\\\\\\\times 100 = 99.97\\\\\\\\%&quot;,&quot;id&quot;:&quot;JRDJAUNRCQ&quot;}\\\" data-component-name=\\\"LatexBlockToDOM\\\"></div><p>But it is above the level that the mobile team can tolerate (120 minutes downtime in 30 days):</p><div class=\\\"latex-rendered\\\" data-attrs=\\\"{&quot;persistentExpression&quot;:&quot;SLO_{mobile} = \\\\\\\\frac { 43800-120 }{43800} \\\\\\\\times 100 = 99.72\\\\\\\\%&quot;,&quot;id&quot;:&quot;CRGTPNAVAE&quot;}\\\" data-component-name=\\\"LatexBlockToDOM\\\"></div><p>So, we have <code>99.93%</code>, <code>99.97%</code>, and <code>9.72%</code>. Which one should we pick?</p><div class=\\\"captioned-image-container\\\"><figure><a class=\\\"image-link image2 is-viewable-img\\\" target=\\\"_blank\\\" href=\\\"https://substackcdn.com/image/fetch/$s_!xH-H!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F0ec62079-bcea-47fa-aafc-e3f7b6ed0f9a_1054x876.png\\\" data-component-name=\\\"Image2ToDOM\\\"><div class=\\\"image2-inset\\\"><picture><source type=\\\"image/webp\\\" srcset=\\\"https://substackcdn.com/image/fetch/$s_!xH-H!,w_424,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F0ec62079-bcea-47fa-aafc-e3f7b6ed0f9a_1054x876.png 424w, https://substackcdn.com/image/fetch/$s_!xH-H!,w_848,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F0ec62079-bcea-47fa-aafc-e3f7b6ed0f9a_1054x876.png 848w, https://substackcdn.com/image/fetch/$s_!xH-H!,w_1272,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F0ec62079-bcea-47fa-aafc-e3f7b6ed0f9a_1054x876.png 1272w, https://substackcdn.com/image/fetch/$s_!xH-H!,w_1456,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F0ec62079-bcea-47fa-aafc-e3f7b6ed0f9a_1054x876.png 1456w\\\" sizes=\\\"100vw\\\"><img src=\\\"https://substackcdn.com/image/fetch/$s_!xH-H!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F0ec62079-bcea-47fa-aafc-e3f7b6ed0f9a_1054x876.png\\\" width=\\\"1054\\\" height=\\\"876\\\" data-attrs=\\\"{&quot;src&quot;:&quot;https://substack-post-media.s3.amazonaws.com/public/images/0ec62079-bcea-47fa-aafc-e3f7b6ed0f9a_1054x876.png&quot;,&quot;srcNoWatermark&quot;:null,&quot;fullscreen&quot;:null,&quot;imageSize&quot;:null,&quot;height&quot;:876,&quot;width&quot;:1054,&quot;resizeWidth&quot;:null,&quot;bytes&quot;:78810,&quot;alt&quot;:null,&quot;title&quot;:null,&quot;type&quot;:&quot;image/png&quot;,&quot;href&quot;:null,&quot;belowTheFold&quot;:true,&quot;topImage&quot;:false,&quot;internalRedirect&quot;:null,&quot;isProcessing&quot;:false,&quot;align&quot;:null,&quot;offset&quot;:false}\\\" class=\\\"sizing-normal\\\" alt=\\\"\\\" srcset=\\\"https://substackcdn.com/image/fetch/$s_!xH-H!,w_424,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F0ec62079-bcea-47fa-aafc-e3f7b6ed0f9a_1054x876.png 424w, https://substackcdn.com/image/fetch/$s_!xH-H!,w_848,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F0ec62079-bcea-47fa-aafc-e3f7b6ed0f9a_1054x876.png 848w, https://substackcdn.com/image/fetch/$s_!xH-H!,w_1272,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F0ec62079-bcea-47fa-aafc-e3f7b6ed0f9a_1054x876.png 1272w, https://substackcdn.com/image/fetch/$s_!xH-H!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F0ec62079-bcea-47fa-aafc-e3f7b6ed0f9a_1054x876.png 1456w\\\" sizes=\\\"100vw\\\" loading=\\\"lazy\\\"></picture><div class=\\\"image-link-expand\\\"><div class=\\\"pencraft pc-display-flex pc-gap-8 pc-reset\\\"><button tabindex=\\\"0\\\" type=\\\"button\\\" class=\\\"pencraft pc-reset pencraft icon-container restack-image\\\"><svg aria-hidden=\\\"true\\\" width=\\\"20\\\" height=\\\"20\\\" viewBox=\\\"0 0 20 20\\\" fill=\\\"none\\\" stroke-width=\\\"1.5\\\" stroke=\\\"var(--color-fg-primary)\\\" stroke-linecap=\\\"round\\\" stroke-linejoin=\\\"round\\\" xmlns=\\\"http://www.w3.org/2000/svg\\\"><g><path d=\\\"M2.53001 7.81595C3.49179 4.73911 6.43281 2.5 9.91173 2.5C13.1684 2.5 15.9537 4.46214 17.0852 7.23684L17.6179 8.67647M17.6179 8.67647L18.5002 4.26471M17.6179 8.67647L13.6473 6.91176M17.4995 12.1841C16.5378 15.2609 13.5967 17.5 10.1178 17.5C6.86118 17.5 4.07589 15.5379 2.94432 12.7632L2.41165 11.3235M2.41165 11.3235L1.5293 15.7353M2.41165 11.3235L6.38224 13.0882\\\"></path></g></svg></button><button tabindex=\\\"0\\\" type=\\\"button\\\" class=\\\"pencraft pc-reset pencraft icon-container view-image\\\"><svg xmlns=\\\"http://www.w3.org/2000/svg\\\" width=\\\"20\\\" height=\\\"20\\\" viewBox=\\\"0 0 24 24\\\" fill=\\\"none\\\" stroke=\\\"currentColor\\\" stroke-width=\\\"2\\\" stroke-linecap=\\\"round\\\" stroke-linejoin=\\\"round\\\" class=\\\"lucide lucide-maximize2 lucide-maximize-2\\\"><polyline points=\\\"15 3 21 3 21 9\\\"></polyline><polyline points=\\\"9 21 3 21 3 15\\\"></polyline><line x1=\\\"21\\\" x2=\\\"14\\\" y1=\\\"3\\\" y2=\\\"10\\\"></line><line x1=\\\"3\\\" x2=\\\"10\\\" y1=\\\"21\\\" y2=\\\"14\\\"></line></svg></button></div></div></div></a></figure></div><p>Of course, the API team prefers the smallest SLO (<code>99.72%</code>) because that gives them a higher error budget.</p><p>But that SLO is below the level that the web team needs with its current implementation. What can they do?</p><p>As we discussed in the <a href=\\\"https://blog.alexewerlof.com/p/lagom-slo\\\">\u201Dlagom\u201D SLO</a>, the web team has three options:</p><ol><li><p><strong>Be prepared for outage</strong></p></li><li><p><strong>Share the risk with their consumers (end users)</strong></p></li><li><p><strong>Negotiate with the API team</strong></p></li></ol><p>The negotiation is tricky because the service provider and service consumer have a conflict of interest.</p><ul><li><p>The provider wants to maximize the error budget and may use <a href=\\\"https://blog.alexewerlof.com/p/10x9\\\">the rule of 10x/9</a> to their defense.</p></li><li><p>The consumer wants to maximize the SLO and uses the paying customer experience as an argument</p></li></ul><div class=\\\"subscription-widget-wrap-editor\\\" data-attrs=\\\"{&quot;url&quot;:&quot;https://blog.alexewerlof.com/subscribe?&quot;,&quot;text&quot;:&quot;Subscribe&quot;,&quot;language&quot;:&quot;en&quot;}\\\" data-component-name=\\\"SubscribeWidgetToDOM\\\"><div class=\\\"subscription-widget show-subscribe\\\"><div class=\\\"preamble\\\"><p class=\\\"cta-caption\\\">In a future article, we\u2019ll talk about various SLO negotiation scenarios and techniques. Do you want to get it in your mailbox when it\u2019s out?</p></div><form class=\\\"subscription-widget-subscribe\\\"><input type=\\\"email\\\" class=\\\"email-input\\\" name=\\\"email\\\" placeholder=\\\"Type your email\u2026\\\" tabindex=\\\"-1\\\"><input type=\\\"submit\\\" class=\\\"button primary\\\" value=\\\"Subscribe\\\"><div class=\\\"fake-input-wrapper\\\"><div class=\\\"fake-input\\\"></div><div class=\\\"fake-button\\\"></div></div></form></div></div><p>Finding <em>impactful </em>SLI and <em>reasonable </em>SLO can be very tricky. As a Sr Staff Engineer responsible for a large organization (100+ teams), I have covered more than half of those teams with Service Level Workshops. I\u2019ll be sharing the steps and experience <a href=\\\"https://blog.alexewerlof.com/p/service-level-workshops\\\">in an upcoming post</a>.</p><div><hr></div><p><em><a href=\\\"https://blog.alexewerlof.com/p/faq#%C2%A7payment\\\">My monetization strategy</a>&nbsp;is to give away most content for free. However, these posts take anywhere from a few hours to days to draft, edit, research, illustrate, and publish. I pull these hours from my private time, vacation days and weekends. Recently I went down in working hours and salary by 10% to be able to spend more time on the newsletter. You can support me by sparing a few bucks for a paid subscription. As a token of appreciation, you get access to the Pro-Tips section as well as my book&nbsp;<a href=\\\"https://blog.alexewerlof.com/p/book-intro-reliability-engineering\\\">Reliability Engineering Mindset</a>. Right now, you can get 20% off via&nbsp;<a href=\\\"https://blog.alexewerlof.com/protipsdiscount\\\">this link</a>.</em></p><div class=\\\"captioned-button-wrap\\\" data-attrs=\\\"{&quot;url&quot;:&quot;https://blog.alexewerlof.com/p/slo?utm_source=substack&utm_medium=email&utm_content=share&action=share&quot;,&quot;text&quot;:&quot;Share&quot;}\\\" data-component-name=\\\"CaptionedButtonToDOM\\\"><div class=\\\"preamble\\\"><p class=\\\"cta-caption\\\">If you find this post insightful, please share it in your circles to inspire others.</p></div><p class=\\\"button-wrapper\\\" data-attrs=\\\"{&quot;url&quot;:&quot;https://blog.alexewerlof.com/p/slo?utm_source=substack&utm_medium=email&utm_content=share&action=share&quot;,&quot;text&quot;:&quot;Share&quot;}\\\" data-component-name=\\\"ButtonCreateButton\\\"><a class=\\\"button primary\\\" href=\\\"https://blog.alexewerlof.com/p/slo?utm_source=substack&utm_medium=email&utm_content=share&action=share\\\"><span>Share</span></a></p></div><h2>Pro-Tips</h2>\",\"has_dynamic_content\":false,\"truncated_body_text\":\"Service Level Objective (SLO) sets the reliability expectation for the service based on how the service consumer perceives reliability (SLI).\",\"wordcount\":1516,\"post_preview_limit\":null,\"language\":\"en\",\"postTags\":[{\"id\":\"1d165f42-7948-43e1-bcf4-aa24c765ac39\",\"publication_id\":1002265,\"name\":\"observability\",\"slug\":\"observability\",\"hidden\":false},{\"id\":\"534a54d4-65f3-4e24-88c0-c603442c7530\",\"publication_id\":1002265,\"name\":\"slo\",\"slug\":\"slo\",\"hidden\":false},{\"id\":\"ae2bf941-bf61-45c2-a8b9-a6dc27247c3a\",\"publication_id\":1002265,\"name\":\"service levels\",\"slug\":\"service-levels\",\"hidden\":false}],\"postCountryBlocks\":[],\"headlineTest\":null,\"coverImagePalette\":{\"Vibrant\":{\"rgb\":[252,171,68],\"population\":902},\"DarkVibrant\":{\"rgb\":[23,67,106],\"population\":37},\"LightVibrant\":{\"rgb\":[252,148,76],\"population\":6},\"Muted\":{\"rgb\":[132,64,64],\"population\":2},\"DarkMuted\":{\"rgb\":[79,45,57],\"population\":21},\"LightMuted\":{\"rgb\":[150.47802197802199,63.049450549450555,2.521978021978013],\"population\":0}},\"publishedBylines\":[{\"id\":87732486,\"name\":\"Alex Ewerl\u00F6f\",\"handle\":\"alexewerlof\",\"photo_url\":\"https://substackcdn.com/image/fetch/f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg\",\"bio\":\"Writes about technical leadership, growth mindset, and system reliability engineering. Senior Staff Engineer, MSc Systems Engineering from KTH, Stockholmer, dad, amateur artist. Read more here: https://www.alexewerlof.com/who\",\"profile_set_up_at\":\"2022-07-14T22:27:32.130Z\",\"reader_installed_at\":\"2022-10-11T17:24:45.190Z\",\"publicationUsers\":[{\"id\":947579,\"user_id\":87732486,\"publication_id\":1002265,\"role\":\"admin\",\"public\":true,\"is_primary\":true,\"publication\":{\"id\":1002265,\"name\":\"Alex Ewerl\u00F6f Notes\",\"subdomain\":\"alexewerlof\",\"custom_domain\":\"blog.alexewerlof.com\",\"custom_domain_optional\":false,\"hero_text\":\"Technical Leadership, Reliability Engineering, Growth\",\"logo_url\":\"https://substack-post-media.s3.amazonaws.com/public/images/8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png\",\"author_id\":87732486,\"primary_user_id\":87732486,\"theme_var_background_pop\":\"#786CFF\",\"created_at\":\"2022-07-14T22:27:58.683Z\",\"email_from_name\":\"Alex Ewerl\u00F6f Notes\",\"copyright\":\"Alex Ewerl\u00F6f\",\"founding_plan_name\":\"VIP supporter\",\"community_enabled\":true,\"invite_only\":false,\"payments_state\":\"enabled\",\"language\":null,\"explicit\":false,\"homepage_type\":\"newspaper\",\"is_personal_mode\":false,\"logo_url_wide\":\"https://substack-post-media.s3.amazonaws.com/public/images/bd56dc7c-4b9f-43f2-99a1-ecc995284940_1200x256.png\"}},{\"id\":8561877,\"user_id\":87732486,\"publication_id\":8361889,\"role\":\"admin\",\"public\":true,\"is_primary\":false,\"publication\":{\"id\":8361889,\"name\":\"AI Reliability Engineering\",\"subdomain\":\"aireliabilityengineering\",\"custom_domain\":null,\"custom_domain_optional\":false,\"hero_text\":\"From the Author of Reliability Engineering Mindset but focused on AI systems and components.\",\"logo_url\":\"https://substackcdn.com/image/fetch/f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg\",\"author_id\":87732486,\"primary_user_id\":null,\"theme_var_background_pop\":\"#FF6719\",\"created_at\":\"2026-03-18T10:58:12.396Z\",\"email_from_name\":null,\"copyright\":\"Alex Ewerl\u00F6f\",\"founding_plan_name\":null,\"community_enabled\":true,\"invite_only\":false,\"payments_state\":\"disabled\",\"language\":null,\"explicit\":false,\"homepage_type\":\"newspaper\",\"is_personal_mode\":false,\"logo_url_wide\":null}}],\"twitter_screen_name\":\"alexewerlof\",\"is_guest\":false,\"bestseller_tier\":null,\"status\":{\"bestsellerTier\":null,\"subscriberTier\":null,\"leaderboard\":null,\"vip\":false,\"badge\":null,\"subscriber\":null}}],\"reaction\":null,\"reaction_count\":19,\"comment_count\":0,\"child_comment_count\":0,\"audio_items\":[{\"post_id\":142248697,\"voice_id\":\"en-US-OnyxTurboMultilingualNeural\",\"audio_url\":null,\"type\":\"tts\",\"status\":\"paywalled\"}],\"is_geoblocked\":false,\"hidden\":true,\"hasCashtag\":false,\"section\":{\"id\":67723,\"created_at\":\"2023-05-31T19:57:24.859Z\",\"updated_at\":\"2024-03-22T13:16:12.203Z\",\"publication_id\":1002265,\"name\":\"Reliability Engineering\",\"description\":\"Concepts that help you with building reliable systems and architecture\",\"slug\":\"sre\",\"is_podcast\":false,\"is_live\":true,\"is_default_on\":true,\"sibling_rank\":1,\"port_status\":\"success\",\"logo_url\":null,\"hide_from_navbar\":false,\"email_from_name\":\"\",\"hide_posts_from_pub_listings\":false,\"email_banner_url\":null,\"cover_photo_url\":null,\"hide_intro_title\":false,\"hide_intro_subtitle\":false,\"ignore_publication_email_settings\":false,\"custom_config\":{},\"unifiedPodcastSettings\":null,\"showLinks\":[],\"podcastSettings\":null,\"pageTheme\":{\"id\":51609,\"publication_id\":1002265,\"section_id\":67723,\"page\":null,\"page_hero\":\"default\",\"page_posts\":\"grid\",\"show_podcast_links\":true,\"hero_alignment\":\"center\"},\"podcastPalette\":{\"DarkMuted\":{\"population\":72,\"rgb\":[73,153,137]},\"DarkVibrant\":{\"population\":6013,\"rgb\":[4,100,84]},\"LightMuted\":{\"population\":7,\"rgb\":[142,198,186]},\"LightVibrant\":{\"population\":3,\"rgb\":[166,214,206]},\"Muted\":{\"population\":6,\"rgb\":[92,164,156]},\"Vibrant\":{\"population\":5,\"rgb\":[76,164,146]}},\"spotify_podcast_settings\":null,\"unified_podcast_settings\":null}},\"comments\":[],\"canonicalUrl\":\"https://blog.alexewerlof.com/p/slo\",\"inlineComments\":false,\"readerIsSearchCrawler\":false,\"ogUrl\":\"https://blog.alexewerlof.com/p/slo\",\"bannedFromNotes\":false,\"themeVariables\":{\"color_theme_bg_pop\":\"#FFBC52\",\"background_pop\":\"#FFBC52\",\"color_theme_bg_web\":\"#001426\",\"cover_bg_color\":\"#001426\",\"cover_bg_color_secondary\":\"#0f2233\",\"background_pop_darken\":\"#ffb238\",\"print_on_pop\":\"#ffffff\",\"color_theme_bg_pop_darken\":\"#ffb238\",\"color_theme_print_on_pop\":\"#ffffff\",\"color_theme_bg_pop_20\":\"rgba(255, 188, 82, 0.2)\",\"color_theme_bg_pop_30\":\"rgba(255, 188, 82, 0.3)\",\"print_pop\":\"#ffbc52\",\"color_theme_accent\":\"#ffbc52\",\"cover_print_primary\":\"#ffffff\",\"cover_print_secondary\":\"#d9d9d9\",\"cover_print_tertiary\":\"#d9d9d9\",\"cover_border_color\":\"#ffffff\",\"font_family_headings_preset\":\"'SF Pro Display', -apple-system, system-ui, BlinkMacSystemFont, 'Inter', 'Segoe UI', Roboto, Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'\",\"font_weight_headings_preset\":900,\"font_family_body_preset\":\"Merriweather,sans-serif\",\"font_weight_body_preset\":400,\"font_preset_heading\":\"sans\",\"font_preset_body\":\"fancy_serif\",\"home_hero\":\"feature-media\",\"home_posts\":\"custom\",\"home_show_top_posts\":true,\"web_bg_color\":\"#001426\",\"background_contrast_1\":\"#0f2233\",\"background_contrast_2\":\"#223443\",\"background_contrast_3\":\"#485663\",\"background_contrast_4\":\"#6d7882\",\"background_contrast_5\":\"#aeb5ba\",\"color_theme_bg_contrast_1\":\"#0f2233\",\"color_theme_bg_contrast_2\":\"#223443\",\"color_theme_bg_contrast_3\":\"#485663\",\"color_theme_bg_contrast_4\":\"#6d7882\",\"color_theme_bg_contrast_5\":\"#aeb5ba\",\"color_theme_bg_elevated\":\"#0f2233\",\"color_theme_bg_elevated_secondary\":\"#223443\",\"color_theme_bg_elevated_tertiary\":\"#485663\",\"color_theme_detail\":\"#192b3c\",\"background_contrast_pop\":\"rgba(255, 188, 82, 0.4)\",\"color_theme_bg_contrast_pop\":\"rgba(255, 188, 82, 0.4)\",\"theme_bg_is_dark\":\"1\",\"print_on_web_bg_color\":\"hsl(208.4210526315789, 25.00000000000006%, 90.74509803921569%)\",\"print_secondary_on_web_bg_color\":\"#99a1a8\",\"footer_bg_color\":\"#000C17\",\"footer_bg_color_h\":\"208.69565217391306\",\"footer_bg_color_s\":\"100%\",\"footer_bg_color_l\":\"4.509803921568627%\",\"print_on_footer_bg_color\":\"hsl(208.69565217391306, 25.000000000000057%, 90.45098039215686%)\",\"print_secondary_on_footer_bg_color\":\"#999ea2\",\"footer_bg_contrast_1\":\"#0f1b25\",\"footer_bg_contrast_2\":\"#222d36\",\"footer_bg_contrast_3\":\"#485158\",\"footer_bg_contrast_4\":\"#6d737a\",\"footer_bg_elevated\":\"#0f1b25\",\"footer_bg_elevated_secondary\":\"#222d36\",\"footer_bg_elevated_tertiary\":\"#485158\",\"footer_detail_color\":\"#19242e\",\"background_pop_rgb\":\"255, 188, 82\",\"color_theme_bg_pop_rgb\":\"255, 188, 82\",\"color_theme_accent_rgb\":\"255, 188, 82\"},\"recentEpisodes\":null,\"trackFrontendVisit\":true,\"activeLiveStream\":null,\"freeTrialCoupon\":{\"id\":\"3cce95ff\",\"trial_period_days\":7},\"defaultCoupon\":null,\"isChatActive\":false,\"publicationPageAlert\":null,\"features\":{},\"browser\":{\"name\":\"Chrome\",\"version\":\"125.0\",\"major\":\"125\"},\"showCookieBanner\":false,\"disabledCookies\":[],\"dd_env\":\"prod\",\"dd_ti\":true}")</script>
<script nonce="-MFX1YSb2IeRINbXaYJYwQ">window._analyticsConfig = JSON.parse("{\"properties\":{\"subdomain\":\"alexewerlof\",\"publication_id\":1002265,\"has_plans\":true,\"pub_community_enabled\":true,\"is_personal_publication\":false,\"section_name\":\"Reliability Engineering\",\"section_slug\":\"sre\",\"section_id\":67723,\"section_is_podcast\":false,\"is_subscribed\":false,\"is_free_subscribed\":false,\"is_author\":false,\"is_contributor\":false,\"is_admin\":false,\"is_founding\":false},\"adwordsAccountId\":\"AW-316245675\",\"adwordsEventSendTo\":\"Tf76CKqcyL4DEKuN5pYB\"}")</script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/lib-router.7371871e.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/55188.571db0c6.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/62357.a0731d37.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/53754.d196682b.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/33485.2686bb5d.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/2237.ae8857e4.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/37707.4614ce58.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/9351.41564edd.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/80821.b2140fcd.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/44292.f3dc2b43.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/70291.7aa24e85.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/17499.1820773d.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/57975.765aca5a.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/19714.2f1bdde5.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/48320.4e726ad5.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/93000.f03f24de.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/44014.f579d62b.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/43745.80c75c78.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/60892.92b9fc9c.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/40646.258e49f2.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/87906.d493457b.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/36479.ce61e623.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/17706.015b0f71.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/93977.f1207089.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/37606.b91ab2ef.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/94311.b93f6845.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/89356.66161d1e.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/21262.211a7337.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/47925.24a01d36.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/80220.03bd4c41.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/71505.3dc43e33.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/11100.5d148f2c.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/3663.86d95e8c.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/18725.a5a682c3.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/86118.ff1ec843.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/93519.7fe128ac.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/84828.c78aabc1.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/5075.d6e9f8ec.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/29231.a7af5911.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/56725.2b32bbb6.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/42336.f1c17ded.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/89879.1d0af2b9.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/70793.951c11cb.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/39522.58e078b0.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/53164.dfde36c8.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/74584.94c6b3f1.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/71199.a327e9f4.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/63266.8bb0d59c.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/47358.8f5c5991.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/4492.cb326b80.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/88089.680833b5.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/97348.df6a856d.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/52109.cf3bcc2c.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/56256.8a1bc5dd.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/77410.3f20fb36.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/25058.bdbc4e21.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/58483.3adddb8a.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/94881.0a97506f.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/27386.09a9082f.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/10174.7f0face7.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/92610.a4fc1daf.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/91214.cb10b4b8.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/11244.b723f409.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/99260.28b0ed6a.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/48445.7d5c5ba3.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/76768.9a2f2bae.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/41932.6c688f22.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/12114.979fb38e.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/48409.9732c6f9.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/26252.4f5ae3be.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/53871.2923c5c9.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/18494.588a06d1.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/99068.bd2e1fba.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/91850.79d3f415.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/49047.c7f428fb.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/16075.098bcbcf.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/28856.2eb51db5.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/95396.72d1d844.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/63175.bbf1c283.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/74628.2e8ed950.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/32552.889dd584.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/27313.c287f2d8.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/mainReactRouter.6c265246.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/91507.9b9761ae.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/54770.b40bf629.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/30054.07cd629b.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/78118.35b48b09.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/57051.f37fb930.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/78191.24075434.js" charset="utf-8"></script>
<script nonce="-MFX1YSb2IeRINbXaYJYwQ" nomodule>
(function() {
var message = 'Your browser does not support modern JavaScript modules. Please upgrade your browser for the best experience.';
var warningDiv = document.createElement('div');
warningDiv.style.color = 'red';
warningDiv.style.padding = '10px';
warningDiv.style.margin = '10px 0';
warningDiv.style.border = '1px solid red';
warningDiv.style.backgroundColor = 'lightyellow';
warningDiv.innerText = message;
document.body.prepend(warningDiv);
})();
</script>
<!-- Datadog Analytics -->
<script nonce="-MFX1YSb2IeRINbXaYJYwQ">
(function(h,o,u,n,d) {
h=h[d]=h[d]||{q:[],onReady:function(c){h.q.push(c)}}
d=o.createElement(u);d.async=1;d.src=n
n=o.getElementsByTagName(u)[0];n.parentNode.insertBefore(d,n)
})(window,document,'script','https://www.datadoghq-browser-agent.com/us1/v5/datadog-rum.js','DD_RUM')
window.DD_RUM.onReady(function() {
window.DD_RUM.init({
clientToken: 'puba71073f072643721169b68f352438710',
applicationId: '2e321b35-c76b-4073-8d04-cc9a10461793',
site: 'datadoghq.com',
service: 'web',
env: window._preloads.dd_env,
version: '8b4c00716b2bc0f7ca1fded553014f7e37b5b07a',
sessionSampleRate: 1,
sessionReplaySampleRate: 10,
trackUserInteractions: window._preloads.dd_ti,
trackResources: true,
trackLongTasks: true,
defaultPrivacyLevel: 'mask-user-input',
allowedTracingUrls: [/https?:\/\/(.+\/.)?substack(cdn)?\.com/]
});
})
</script>
<!-- End Datadog Analytics -->
<!-- Cloudflare Web Analytics -->
<script defer src="https://static.cloudflareinsights.com/beacon.min.js" data-cf-beacon='{"token": "216309cffb464db4b0e02daf0b8e8060"}'></script>
<!-- End Cloudflare Web Analytics -->
<!-- Fallback tracking pixels -->
<noscript>
<style>
#nojs-banner {
position: fixed;
bottom: 0;
left: 0;
padding: 16px 16px 16px 32px;
width: 100%;
box-sizing: border-box;
background: red;
color: white;
font-family: -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
font-size: 13px;
line-height: 13px;
}
#nojs-banner a {
color: inherit;
text-decoration: underline;
}
</style>
<div id="nojs-banner">
This site requires JavaScript to run correctly. Please <a href="https://enable-javascript.com/" target="_blank">turn on JavaScript</a> or unblock scripts
</div>
</noscript>
<script type="module" src="https://static.cloudflareinsights.com/beacon.min.js/v31edd6df95cf4e85bb4c19e7a9bdbcba1788362987495" integrity="sha512-iIg7k2xntmwu6/uSb5tpc/hySgZc4eoL31yB29W6tJFo2akwjPWcEqnCEdJvGexCL0KEQwVYv5BlowfhVz26hg==" nonce="-MFX1YSb2IeRINbXaYJYwQ" data-cf-beacon='{"version":"2024.11.0","token":"68cfe66b5c4749e2ba64d4d9640c04c0","spa":2}' crossorigin="anonymous"></script>
</body>
</html>