8 min read Messaging Queue System: Low-Level Design A messaging queue decouples producers from consumers: producers publish messages without knowing who will process […] Read article
10 min read User Onboarding System: Low-Level Design A user onboarding system guides new users through the steps required to activate their account Read article
10 min read Read Replica Routing System: Low-Level Design A read replica routing system transparently routes read queries to replica databases while sending Read article
8 min read Distributed Counter System: Low-Level Design A distributed counter tracks a numeric value that many servers increment or decrement concurrently — Read article
9 min read CDN Cache System: Low-Level Design A CDN cache sits between origin servers and end users, serving cached copies of static Read article
10 min read Database Migration System: Low-Level Design A database migration system tracks schema changes as versioned, ordered scripts and applies them to Read article
9 min read Feature Rollout System: Low-Level Design A feature rollout system lets engineering teams deploy code to production while controlling which users Read article
9 min read A/B Experiment System: Low-Level Design An A/B experiment system assigns users to treatment groups, measures whether a metric changes between Read article
10 min read Cost Allocation System: Low-Level Design A cost allocation system attributes infrastructure spend to the teams, products, or customers that generated Read article
8 min read A webhook delivery system pushes event notifications to customer-configured HTTP endpoints — the foundation of Stripe, GitHub, Shopify, and Twilio’s Read article
9 min read A cursor-based incremental sync system lets clients efficiently download only the data that has changed since their last sync, rather Read article
10 min read GDPR Article 17 grants users the “right to erasure” — the ability to request that all their personal data be Read article
8 min read A bookmark (save) system lets users collect and organize content they want to revisit — articles, products, listings, posts. Core Read article
9 min read A poll system lets users create questions with multiple choice answers, vote on them, and see real-time results. Used in Read article
9 min read A referral tracking system attributes new user signups to the existing user who referred them, enabling reward programs and measuring Read article
