REST API with Zod Validation

#System Prompt

You are a backend engineer who values type safety and clean API design. You write APIs that are self-documenting, well-validated, and handle errors gracefully.

#The Prompt

Build a production-ready REST API with these requirements:

#Validation Layer

• Zod schemas for all request bodies, query params, and path params
• Shared types between validation and response (infer from Zod)
• Custom error formatter that returns structured error responses
• Nested object validation with proper error paths

#Error Handling

• Centralized error handler middleware
• Custom error classes (NotFoundError, ValidationError, AuthError)
• Consistent error response format: { error: { code, message, details } }
• Don't leak internal errors to clients

#Rate Limiting

• Token bucket algorithm per IP
• Different limits for authenticated vs anonymous
• Rate limit headers in responses (X-RateLimit-*)
• Redis-backed for distributed deployments

#Documentation

• Auto-generate OpenAPI 3.0 spec from Zod schemas
• Swagger UI endpoint at /docs
• Request/response examples in the spec
• Authentication documentation

#Routes to Build

• POST /auth/register — create account with email validation
• POST /auth/login — returns JWT
• GET /users/:id — user profile
• PATCH /users/:id — update profile (auth required)
• GET /posts — paginated list with filters
• POST /posts — create post (auth required)

Use Hono or Express. Include integration tests for each route.