api-design-principles

REST API design for scalability focuses on stateless resource modeling, proper HTTP method semantics, and pagination strategies. Structure endpoints around nouns (resources), use correct status codes, implement cursor or offset-based pagination, and separate concerns across multiple endpoints to avoid monolithic payloads and enable horizontal scaling.

REST suits simpler, strongly-typed resource hierarchies with predictable access patterns; GraphQL excels when clients need flexible, fine-grained data queries and you can manage schema complexity. REST is easier to cache and monitor; GraphQL reduces over-fetching and bandwidth but requires resolver optimization and N+1 prevention with tools like DataLoader.

API versioning strategies include URL paths (/v1/, /v2/), headers, or query parameters. Maintain backward compatibility by deprecating fields gradually, supporting multiple versions simultaneously, and communicating breaking changes clearly. Document migration paths so clients can upgrade without service disruption.

Common pitfalls include inconsistent error response formats, missing or unclear pagination, poor HTTP semantics, inadequate documentation, and N+1 query problems in GraphQL. Establish team standards for error handling, implement structured error objects with codes and messages, version your schema, and use DataLoader to batch resolver queries.

Create a shared design specification covering endpoint naming conventions, error formats, authentication patterns, and pagination rules. Use OpenAPI for REST or GraphQL schema documentation, enforce standards in code review, and maintain a design guide that covers HATEOAS, versioning, and governance policies for consistency across microservices.