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name: api-patterns description: API design principles and decision-making. REST vs GraphQL vs tRPC selection, response formats, versioning, pagination. when_to_use: "When designing REST/GraphQL/tRPC APIs, defining response formats, versioning, pagination, or API authentication. NOT for UI/frontend work." allowed-tools: Read, Write, Edit, Glob, Grep

API Patterns

API design principles and decision-making for 2025. Learn to THINK, not copy fixed patterns.

🎯 Selective Reading Rule

Read ONLY files relevant to the request! Check the content map, find what you need.

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📑 Content Map

| File | Description | When to Read | |------|-------------|--------------| | api-style.md | REST vs GraphQL vs tRPC decision tree | Choosing API type | | rest.md | Resource naming, HTTP methods, status codes | Designing REST API | | response.md | Envelope pattern, error format, pagination | Response structure | | graphql.md | Schema design, when to use, security | Considering GraphQL | | trpc.md | TypeScript monorepo, type safety | TS fullstack projects | | versioning.md | URI/Header/Query versioning | API evolution planning | | auth.md | JWT, OAuth, Passkey, API Keys | Auth pattern selection | | rate-limiting.md | Token bucket, sliding window | API protection | | documentation.md | OpenAPI/Swagger best practices | Documentation | | security-testing.md | OWASP API Top 10, auth/authz testing | Security audits |

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🔗 Related Skills

| Need | Skill | |------|-------| | API implementation | @[skills/backend-development] | | Data structure | @[skills/database-design] | | Security details | @[skills/security-hardening] |

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✅ Decision Checklist

Before designing an API:

• [ ] Asked user about API consumers?
• [ ] Chosen API style for THIS context? (REST/GraphQL/tRPC)
• [ ] Defined consistent response format?
• [ ] Planned versioning strategy?
• [ ] Considered authentication needs?
• [ ] Planned rate limiting?
• [ ] Documentation approach defined?

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❌ Anti-Patterns

DON'T:

• Default to REST for everything
• Use verbs in REST endpoints (/getUsers)
• Return inconsistent response formats
• Expose internal errors to clients
• Skip rate limiting

DO:

• Choose API style based on context
• Ask about client requirements
• Document thoroughly
• Use appropriate status codes

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Script

| Script | Purpose | Command | |--------|---------|---------| | scripts/api_validator.py | API endpoint validation | python scripts/api_validator.py <project_path> |