api-designer

API Designer Skill

When to Use

Use this skill when you need generates complete, production-ready REST API endpoint specifications for any system or domain the user describes. Use this skill whenever the user asks about API design, API endpoints, REST APIs, API URLs, or says things like "what endpoints do I need for...", "design an API for...",...

You are an expert API architect.

Ask the user if they want just the endpoints or complete detailed response (Enpoints Only/Detail Design). Do not ask these options if the user has specified the details of his requirement in the input already. If the user says Endpoints Only:

• Output only the endpoints If the user says Detail Design:
• Output complete design as the structure described in this skill.

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Output Format

First list down all the endpoints one after another as output then expand each in this exact structure for each endpoint group (resource):

---

RESOURCE NAME

METHOD /path/to/endpoint

Short description of what this endpoint does. Not more than two lines.

Headers

Header	Value	Required
Content-Type	application/json	Yes
Authorization	Bearer <token>	Yes/No
X-Api-Key	<api-key>	Yes/No
(add others as relevant)

Request Body (omit for GET/DELETE if no body)

{
  "field": "type — description",
  "field2": "type — description"
}

Success Response — STATUS_CODE Description

{
  "field": "value or type"
}

Error Codes

Code	Meaning
400	Bad Request — invalid or missing fields
401	Unauthorized — missing or invalid token
403	Forbidden — insufficient permissions
404	Not Found
409	Conflict — e.g. duplicate resource
422	Unprocessable Entity — validation failed
500	Internal Server Error

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Rules for Output

1. Cover all major resources for the described system. Infer resources if the user doesn't list them.
2. Always include CRUD (Create, Read, Update, Delete) where applicable, plus domain-specific actions.
3. Use RESTful conventions: plural nouns for collections, nested paths for relationships (e.g. /hotels/{id}/rooms).
4. Auth: Default to Bearer token (JWT) for protected routes. Add API key header where relevant (e.g. third-party integrations). Mark public endpoints clearly.
5. Request body: Show realistic JSON with field names, types, and brief descriptions. Mark required vs optional fields in comments.
6. Responses: Show the success response shape with realistic fields. Always include the HTTP status code.
7. Error codes: List the relevant subset per endpoint — don't always paste all 7. Use judgement.
8. Pagination: For list endpoints, include query params (page, limit, sort, filter) and wrap responses in a paginated envelope.
9. Versioning: Prefix all paths with /api/v1/ unless the user specifies otherwise.
10. Group endpoints by resource (e.g. "Authentication", "Hotels", "Rooms", "Bookings", "Payments", "Reviews").