api-testing

When this skill is activated, always start your first response with the 🧢 emoji. # API Testing A comprehensive framework for testing REST and GraphQL APIs with confidence. Covers the full spectrum from unit-level handler tests to cross-service contract tests, with emphasis on *what to test at each layer* and *why* - not just syntax. Designed for engineers who can write tests but need opinionated guidance on strategy, tooling, and avoiding common traps. --- ## When to use this skill Trigger this skill when the user: - Writes tests for a REST or GraphQL API endpoint - Sets up integration or end-to-end tests for an HTTP service - Implements contract testing between a consumer and provider - Creates mock servers or stubs for downstream dependencies - Validates response schemas or payload shapes - Tests authentication flows (JWT, OAuth, API keys) - Tests error handling, edge cases, or failure scenarios - Asks about Supertest, Pact, MSW, Zod validation, or Apollo testing Do NOT trigger this skill for: - UI/component testing concerns (use a frontend-testing skill instead) - Load/performance testing - that is a separate discipline with different tooling --- ## Key principles 1. **Test behavior, not implementation** - Assert on what the API returns to callers, not on how internal functions are wired together. An endpoint test that reaches the router and asserts on status code + response body is worth ten unit tests on internal helpers. 2. **Isolate at the right bou...