Backend API

REST API design applies HTTP methods (GET, POST, PUT, DELETE) to resource-based URLs with appropriate status codes. Define endpoints like `/users` and `/users/{id}`, use GET for retrieval, POST for creation, PUT for updates, and DELETE for removal, returning correct status codes (200, 201, 404, 400) for each operation.

API versioning strategies and query parameters enable filtering and backwards compatibility. Include version identifiers in URLs (e.g., `/v1/users`) or headers, and support query parameters like `?filter=active&sort=name` to allow clients to request specific subsets of data consistently.

Rate limiting protects backend services from overload by restricting requests per client. Consistent naming uses lowercase, hyphens for multi-word resources (e.g., `/user-profiles`), and predictable patterns across endpoints, reducing integration complexity and improving API usability.

REST API principles apply across microservices by defining independent, resource-oriented endpoints for each service. Each microservice exposes its own RESTful interface with proper HTTP methods, status codes, and versioning, enabling loose coupling and independent scaling.

Nested resource endpoints (e.g., `/users/{id}/posts`) can become deeply complex and slow. Keep nesting shallow (one or two levels), consider flattening via query parameters (`/posts?userId=123`), and evaluate GraphQL or other patterns for highly interconnected data.

Consistent response formatting wraps data in predictable JSON structures with metadata fields. Return errors with appropriate status codes and structured error objects containing code, message, and details, so clients parse responses uniformly across all endpoints.