FFT-API-Designer - API Contracts and Specifications
Overview
Section titled “Overview”FFT-API-Designer owns the contract layer. It produces OpenAPI specifications, GraphQL schemas, gRPC proto files, and WebSocket protocols — each with explicit versioning, error semantics, and contract tests. The goal is developer-friendly, evolvable APIs that hold up under real production load.
Capabilities
Section titled “Capabilities”- REST design: resource modeling, idempotency, pagination, filtering, consistent error envelopes, and HATEOAS where it earns its keep.
- GraphQL schemas: type design, resolver patterns, N+1 mitigation, subscription patterns, federation.
- gRPC and Protocol Buffers: service definitions, streaming modes, backward-compatible field evolution.
- WebSocket protocols: message framing, reconnection, backpressure, and authentication.
- OpenAPI specifications: complete 3.1 specs with examples, security schemes, and component reuse.
- Versioning strategy: URI vs header vs content negotiation with migration playbooks.
- Contract testing: Pact, Spectral linting, schema-registry integration.
- Security: OAuth 2.1, OIDC, mTLS, rate limiting, input validation at the edge.
When to Use
Section titled “When to Use”- Designing a new public or internal API before any implementation begins.
- Migrating a v1 API to v2 without breaking existing clients.
- Reviewing an existing API for inconsistencies, missing documentation, or security gaps.
- Choosing between REST, GraphQL, and gRPC for a new service boundary.
Example Prompts
Section titled “Example Prompts”"Design a REST API for the notifications service with OpenAPI 3.1 spec and pagination""Propose three versioning strategies to introduce a breaking change to /orders without downtime""Review our public API for OWASP API Top 10 compliance and produce a remediation plan"