irahardianto API Design Principles
RESTful Standards
URLs: plural nouns (/api/v1/users), hierarchical (/users/:id/orders), no verbs.
Methods: GET=read (safe, idempotent, cacheable), POST=create, PUT=replace (idempotent), PATCH=partial update (idempotent), DELETE=remove (idempotent).
Versioning: URL path /api/v1/users.
Pagination: default 20, max 100. Cursor (?cursor=abc123) or offset (?page=2&limit=20).
Filter/Sort: ?status=active&role=admin, ?sort=created_at:desc,name:asc, ?q=search+term.
Status Codes
Success: 200 OK (GET/PUT/PATCH), 201 Created (POST), 204 No Content (DELETE).
4xx (client can fix):
- 400 Bad Request — validation (invalid email, missing field). Detailed field errors.
- 401 Unauthorized — auth failed (invalid/expired/missing token)
- 403 Forbidden — permission denied (identified but lacks access)
- 404 Not Found — doesn't exist (or permission to know it exists)
- 409/422 — business rule violation (duplicate, insufficient balance)
- 429 — rate limited. Wait + retry.
5xx (system): 500/502/503 — generic message + correlationId. User: retry later.
Success Response
{
"data": { /* resource or array */ },
"meta": {
"total": 100,
"page": 1,
"perPage": 20
},
"links": {
"self": "/api/v1/users?page=1",
"next": "/api/v1/users?page=2",
"prev": null
}
}
Error Response
{
"status": "error",
"code": 400,
"error": {
"code": "VALIDATION_ERROR",
"message": "Invalid email format",
"details": {
"field": "email",
"reason": "Must be a valid address"
},
"correlationId": "req-1234567890",
"doc_url": "https://..."
}
}
Related
- Error Handling GEMINI.md § Error Handling Principles
- Security Mandate GEMINI.md § Security Mandate
- Security Principles GEMINI.md § Security Principles
- Logging Mandate GEMINI.md § Logging and Observability Mandate
- Data Serialization @.gemini/skills/data-serialization-principles/SKILL.md