REST — Part 2: Production Architecture, Status Codes & Advanced Patterns

maang.io System Design Series

What is this?

Back to our library. Part 1 covered how the place is organized — every book has an address, you use a few standard verbs. This part is about everything that makes a library actually work at scale: the clear signs that tell you "checked out" vs "lost" vs "we're closed for maintenance" (status codes), the reference copies kept near the door so you don't trek to the basement (caching), the way they roll out a new catalog system without throwing away every old library card (versioning), and how they hand you results 20 at a time instead of dumping the whole floor on you (pagination).

The one-line idea: a production REST API isn't just resources and verbs — it's the discipline around them: precise status codes, real caching, graceful versioning, and pagination, so the API stays fast, evolvable, and honest as it grows to millions of requests.

The resource model from Part 1 is the skeleton. This is the muscle. Let's build it.