Approval Workflow System: Low-Level Design An approval workflow routes a request — a purchase order, a content post, a contract, […]
Job Queue System: Low-Level Design A job queue system schedules and executes background work: sending emails, resizing images, generating reports,
Search Index System: Low-Level Design A search index system converts raw documents into a structure that supports fast full-text queries.
Read Replica Routing System: Low-Level Design A read replica routing system transparently routes read queries to replica databases while sending
User Onboarding System: Low-Level Design A user onboarding system guides new users through the steps required to activate their account
Messaging Queue System: Low-Level Design A messaging queue decouples producers from consumers: producers publish messages without knowing who will process
Database Migration System: Low-Level Design A database migration system tracks schema changes as versioned, ordered scripts and applies them to
CDN Cache System: Low-Level Design A CDN cache sits between origin servers and end users, serving cached copies of static
Distributed Counter System: Low-Level Design A distributed counter tracks a numeric value that many servers increment or decrement concurrently —
Cost Allocation System: Low-Level Design A cost allocation system attributes infrastructure spend to the teams, products, or customers that generated
A/B Experiment System: Low-Level Design An A/B experiment system assigns users to treatment groups, measures whether a metric changes between
Feature Rollout System: Low-Level Design A feature rollout system lets engineering teams deploy code to production while controlling which users
GDPR Article 17 grants users the “right to erasure” — the ability to request that all their personal data be
A cursor-based incremental sync system lets clients efficiently download only the data that has changed since their last sync, rather
A webhook delivery system pushes event notifications to customer-configured HTTP endpoints — the foundation of Stripe, GitHub, Shopify, and Twilio’s
