Web Backend Engineering

Specify and verify API behavior against the project's supported framework/runtime and deployment constraints. Framework syntax alone does not need this skill.

Workflow

1. Inspect routes, schemas, identity/permission model, storage/message boundaries and existing tests. Identify supported versions from manifests/lockfiles and deployment images.
2. Define request/response/error contracts, authorization per resource/action, compatibility and pagination/size limits.
3. Trace writes through transaction boundaries. State idempotency/retry behavior, optimistic concurrency, external side effects and recovery from partial failure.
4. For asynchronous work, define delivery/deduplication/ordering and how status reaches the caller. For GraphQL, bound complexity and check resolver authorization/N+1 behavior.
5. Implement with repository conventions and current official framework documentation. Avoid copying old scaffold versions or adding a service/framework without a real requirement.
6. Check observable contracts: success, denied/invalid/missing cases, race/retry behavior, persistence and failure responses. Measure performance when a claim depends on it.
7. Document externally relevant behavior and report checks/limitations. Use security, distributed-system or operational guidance selectively when the boundary requires it.

Optional recipes

REST compatibility, authentication/authorization, transactions, messages, GraphQL, API tests, documentation, service boundaries, FastAPI, Django, Express.

Recipes are checklists and primary-documentation pointers, not pinned tutorial implementations. Verify version-specific semantics in the installed/project version before adopting a recipe.