--- title: System Design Crash Course: Scaling 100 to 100M Users description: A comprehensive walkthrough of scaling a web application from 100 to 100 million users, structured around four core bottleneck types: compute, reads, writes,... canonical: https://daily.dev/posts/3ngiuticq twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: System Design Crash Course: Scaling 100 to 100M Users | daily.dev og:description: A comprehensive walkthrough of scaling a web application from 100 to 100 million users, structured around four core bottleneck types: compute, reads, writes,... og:url: https://daily.dev/posts/3ngiuticq og:image: https://api.daily.dev/og/posts/3ngiutICq.png og:image:alt: Post cover image og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # System Design Crash Course: Scaling 100 to 100M Users **[Joud Awad](https://daily.dev/sources/iac4jsbu0lv8wbsc85fsh)** · [@joudawad](https://daily.dev/joudawad) · 297 upvotes · 32 comments ## Summary A comprehensive walkthrough of scaling a web application from 100 to 100 million users, structured around four core bottleneck types: compute, reads, writes, and async work. Covers vertical vs. horizontal scaling trade-offs, the Universal Scalability Law, stateless app servers, load balancer layers, caching strategies (cache-aside, materialized views, fan-out on write vs. read), database connection pooling, sharding with consistent hashing, async queues and idempotency, circuit breakers, bulkheads, retry budgets with jitter, rate limiting (token bucket vs. sliding window), multi-region active-active trade-offs, CAP theorem, cell-based architecture for blast radius containment, and cloud cost optimization including reserved instances, storage tiering, and egress pricing. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Community discussion Top comments from developers on daily.dev. **@malibuconpiña** · 2 upvotes > wow, pretty interesting. i just had to take some notes about what i need to learn to understand better how to make systems grow consistently **@epicuser** · 2 upvotes > Thank you so much, these crash courses are a gems and i am super happy you are doing them for free and put all this effort in them 🙏 > > Good luck man! **@jad85** · 2 upvotes > Awesome Awesome Awesome!! Thank you so much man these deep dives are amazing! > > Looking for many more coming! **@aurimarlopes** · 2 upvotes > how to scale 0 to 1 active users ? **@agustinbarrientos** · 2 upvotes > Cell-based isolation would be my first move before active-active multi-region. Smaller failure domains are much easier to debug at 3 a.m. ## Similar posts on daily.dev - [Don’t just attend KubeCon \+ CloudNativeCon, Merge Forward your experience\!](https://daily.dev/posts/don-t-just-attend-kubecon-cloudnativecon-merge-forward-your-experience--l0rpp73x8) · CNCF · 1 upvotes · 0 comments - [Announcing H2 2026 KCDs](https://daily.dev/posts/announcing-h2-2026-kcds-m96goajm1) · CNCF · 1 upvotes · 0 comments - [Two months of Open Community Groups](https://daily.dev/posts/two-months-of-open-community-groups-asf52zhbs) · CNCF · 0 upvotes · 0 comments --- Tags: [#career](https://daily.dev/tags/career), [#backend](https://daily.dev/tags/backend), [#distributed-systems](https://daily.dev/tags/distributed-systems) [View this post on daily.dev](https://daily.dev/posts/3ngiuticq) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"DiscussionForumPosting","mainEntityOfPage":"https://daily.dev/posts/3ngiuticq","headline":"System Design Crash Course: Scaling 100 to 100M Users","text":"Shared: System Design Crash Course: Scaling 100 to 100M Users","url":"https://daily.dev/posts/3ngiuticq","datePublished":"2026-08-10T16:11:39.341Z","dateModified":"2026-08-12T16:15:03.658Z","author":{"@type":"Person","name":"Joud Awad","url":"https://daily.dev/joudawad","image":"https://media.daily.dev/image/upload/s--dOB9RaXY--/f_auto/v1773320801/avatars/avatar_iaC4JsBU0lV8wBsc85fSh?_a=BAMAMiiu0","description":"Principal Solution Architecture ","worksFor":{"@type":"Organization","name":"Metalab","logo":"https://www.google.com/s2/favicons?domain=metalab.com&sz=128"},"interactionStatistic":{"@type":"InteractionCounter","interactionType":{"@type":"EndorseAction"},"userInteractionCount":81900}},"image":"https://media.daily.dev/image/upload/s--foaA6JGU--/f_auto/v1722860399/public/Placeholder%2004","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":297},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":32}],"sharedContent":{"@type":"WebPage","url":"https://api.daily.dev/r/EqIz9bIv4"},"comment":[{"@type":"Comment","text":"wow, pretty interesting. i just had to take some notes about what i need to learn to understand better how to make systems grow consistently","datePublished":"2026-09-08T09:26:35.571Z","url":"https://daily.dev/posts/3ngiutICq#c-C44L5yN6B","author":{"@type":"Person","name":"malibu","url":"https://daily.dev/malibuconpiña","image":"https://lh3.googleusercontent.com/a/ACg8ocJVzEqLEI2KtfKdMiNtpoLGNU6vPiVxtKOYVZI3Ule-pya9ow=s96-c"},"interactionStatistic":{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":2}},{"@type":"Comment","text":"Thank you so much, these crash courses are a gems and i am super happy you are doing them for free and put all this effort in them 🙏\nGood luck man!","datePublished":"2026-08-10T16:16:55.793Z","url":"https://daily.dev/posts/3ngiutICq#c-zczSnpdop","author":{"@type":"Person","name":"EpicUser","url":"https://daily.dev/epicuser","image":"https://media.daily.dev/image/upload/s--O0TOmw4y--/f_auto/v1715772965/public/noProfile"},"interactionStatistic":{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":2}},{"@type":"Comment","text":"Awesome Awesome Awesome!! Thank you so much man these deep dives are amazing!\nLooking for many more coming!","datePublished":"2026-08-10T16:15:10.843Z","url":"https://daily.dev/posts/3ngiutICq#c-Qe5wBOOwz","author":{"@type":"Person","name":"Jad","url":"https://daily.dev/jad85"},"interactionStatistic":{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":2}},{"@type":"Comment","text":"how to scale 0 to 1 active users ?","datePublished":"2026-08-13T08:57:57.104Z","url":"https://daily.dev/posts/3ngiutICq#c-gvhOno8tg","author":{"@type":"Person","name":"Aurimar Lopes","url":"https://daily.dev/aurimarlopes","image":"https://avatars.githubusercontent.com/u/76595232?v=4"},"interactionStatistic":{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":2}},{"@type":"Comment","text":"Cell-based isolation would be my first move before active-active multi-region. Smaller failure domains are much easier to debug at 3 a.m.","datePublished":"2026-08-12T14:28:56.713Z","url":"https://daily.dev/posts/3ngiutICq#c-0KY9z5CXp","author":{"@type":"Person","name":"Agustin Barrientos","url":"https://daily.dev/agustinbarrientos","image":"https://media.daily.dev/image/upload/s--5ayxQnqn--/f_auto/v1788281802/avatars/avatar_wQYYVe5Tbj0NJ7C7qPoa8?_a=BAMAMicg0"},"interactionStatistic":{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":2}}],"isPartOf":{"@type":"WebPage","url":"https://daily.dev/sources/iac4jsbu0lv8wbsc85fsh","name":"Joud Awad"}} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Joud Awad","item":"https://daily.dev/sources/iac4jsbu0lv8wbsc85fsh"},{"@type":"ListItem","position":3,"name":"System Design Crash Course: Scaling 100 to 100M Users"}]} ```