Building REST/HTTP APIs in Golang — stdlib net/http with Go 1.22+ ServeMux pattern routing, handler and middleware design, request decoding and validation, RFC 9457 problem+json error responses, http.Server timeouts, graceful shutdown, context propagation, pagination, idempotency, versioning, CORS, and httptest-based testing. Apply when writing or reviewing HTTP handlers, routers or middleware, designing REST resources and status codes, or when the codebase imports net/http as a server, github.com/go-chi/chi, gin or echo.
