# System Design Atlas

A free reference of worked system design problems with interactive architecture diagrams, covering ranked designs such as a feed, a chat app, a URL shortener, and a rate limiter, plus pages on the technologies behind them.

System Design Atlas is a reference site for distributed systems design, organized into ten foundational concept modules, from data storage and consistency through caching, async messaging, and reliability, that build on each other in order. Fifteen full worked designs, ordered by how often they come up, cover systems such as a social feed, a chat application, a URL shortener, a distributed rate limiter, a notification system, and a payment system, each with architecture diagrams and trade-offs.

Fifteen further pages describe key technologies by name, including PostgreSQL, Redis, Cassandra, DynamoDB, Kafka, and gRPC, stating what each is and when to reach for it. A companion track separately covers data structures and algorithms.

The site frames most design decisions as one of four recurring trade-offs, such as computing a result now versus on demand, or keeping one copy of data versus many, and a beta playground section is also available.

Website: https://atlas-sysdes.vercel.app/