API Design

HTTP APIs are the contract between your service and every client that consumes it. A well-designed API is consistent and predictable: the URL says which resource you are touching, the HTTP method says what happens to it, and the status code plus body say whether it worked and why not. This skill covers designing and reviewing such APIs — resource modeling, HTTP semantics, status codes, error envelopes, pagination, versioning, spec-first OpenAPI 3.x, and authentication basics — REST first, with GraphQL and gRPC covered in passing.

Quick Reference

Core Workflow

Design an endpoint set in five steps: