crud-api-generator

CRUD API Generator

Generates complete, production-ready CRUD endpoints for any entity with proper HTTP status codes, input validation, error handling, and consistent response shapes.

Workflow

1. Gather Entity Info

Before generating, identify:

• Entity name (e.g. User, Product, Order)
• Fields (names, types, required vs optional)
• Framework/language (Express, FastAPI, Django, Next.js API routes, Hono, etc.)
• Database/ORM (Prisma, Mongoose, SQLAlchemy, raw SQL, etc.)
• Auth requirements (public, JWT-protected, role-based)

If the user hasn't specified framework or DB, ask once — or make a reasonable default (Express + Prisma is a safe assumption for Node.js, FastAPI + SQLAlchemy for Python).

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2. Generate the Five Endpoints

Always generate all five operations unless the user explicitly says to skip one:

Operation	Method	Path	Success Code
Create	POST	/entities	201
Read	GET	/entities/:id	200
List	GET	/entities	200
Update	PUT/PATCH	/entities/:id	200
Delete	DELETE	/entities/:id	204

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3. Code Standards

Validation

• Validate required fields on Create and Update
• Return 400 Bad Request with a descriptive message for missing/invalid input
• Use the framework's native validator if available (e.g. Zod, Pydantic, class-validator), otherwise inline checks

Error Handling

• 400 — validation error (missing/invalid fields)
• 404 — entity not found
• 409 — conflict (e.g. duplicate unique field)
• 500 — unexpected server error (always catch and return generic message, log internally)

Response Shape Use consistent JSON envelopes:

// Success
{ "data": { ...entity } }

// List
{ "data": [...entities], "total": 42 }

// Error
{ "error": "Human-readable message" }

Naming

• Route params: :id (or {id} for FastAPI/Django)
• Variables: camelCase for JS/TS, snake_case for Python
• File structure: suggest splitting into router, controller, and service layers for larger apps; inline for small examples

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4. Framework-Specific Patterns

Read the relevant reference file before generating for these frameworks:

• Express (JS/TS): See references/express.md
• FastAPI (Python): See references/fastapi.md
• Next.js App Router: See references/nextjs.md
• Django REST Framework: See references/django.md
• Hono: Follow Express patterns with Hono's c.json() and c.req.json() syntax

For unlisted frameworks, apply the general standards above and match the framework's idiomatic style.

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5. Output Structure

Always output in this order:

1. Schema / Model definition (Prisma schema, Pydantic model, Mongoose schema, etc.)
2. Router / URL config
3. Controller / Handler functions (all five)
4. Validation logic (inline or separate validator file)
5. Usage examples (curl or fetch snippets for each endpoint)

If the codebase is small, combine into one file with clear section comments. For larger apps, split and show the file path for each block.

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6. Optional Extras (offer after main output)

• Pagination on the List endpoint (?page=1&limit=20)
• Soft delete (set deletedAt instead of hard delete)
• Search/filter params on List
• Swagger/OpenAPI annotation stubs
• Unit test stubs for each endpoint