API Design Mastery

Core Philosophy

1. Design for the consumer, not the database — API shape reflects use cases, not schema structure. Consumers should not need to understand your internals.
2. Consistency over cleverness — Uniform patterns across all endpoints reduce cognitive load more than any individual optimization.
3. Additive by default — Plan for backward compatibility from day one. Adding is safe; removing breaks clients.
4. Errors are first-class citizens — Error contracts deserve the same design care as success responses. Use RFC 9457.
5. Pick the right tool — REST for public APIs, GraphQL for multi-client data graphs, tRPC for TypeScript monorepos.

Quick-Start: Common Problems

"Which API style should I use?"