REST vs GraphQL: which to choose?

REST is the better choice for public APIs, simple CRUD applications, and systems where caching is critical. HTTP caching works naturally with REST endpoints (each URL is cacheable), CDNs can cache responses out of the box, and the tooling ecosystem is mature and universally understood. REST is also simpler for teams without GraphQL experience and for services that will be consumed by many third-party clients who expect standard HTTP semantics. Choose GraphQL when clients need flexible data fetching, your API serves multiple frontend platforms with different data needs, or over-fetching/under-fetching is causing performance issues.

Migration is commonly done incrementally by placing a GraphQL layer in front of existing REST endpoints. The GraphQL server acts as an aggregation layer, calling REST APIs internally and presenting a unified graph schema to clients. This approach lets you migrate one resource at a time without disrupting existing REST consumers. Over time, the most frequently accessed REST endpoints can be replaced with direct database queries in the GraphQL resolvers for better performance.

REST excels in cacheable read-heavy scenarios — a CDN can serve REST responses in under 10ms globally. GraphQL reduces total data transfer by fetching exactly what the client needs, eliminating over-fetching that plagues REST APIs returning full resource objects. However, GraphQL queries can be expensive on the server if clients request deeply nested data, requiring query complexity analysis and depth limiting. For mobile applications on slow networks, GraphQL's single-request approach often outperforms REST's multiple-endpoint pattern.

REST has a vastly larger ecosystem because it has been the standard API paradigm for two decades — every language, framework, and tool supports REST natively. API documentation (Swagger/OpenAPI), testing (Postman), monitoring (Datadog), and gateway tools (Kong, AWS API Gateway) all assume REST. GraphQL's ecosystem is younger but mature for production use: Apollo, Relay, Hasura, and Prisma offer excellent developer experiences. For new projects, both ecosystems are sufficient; for enterprise integrations, REST compatibility is often mandatory.

REST APIs are cheaper to implement initially because every backend developer already knows how to build them, and frameworks provide built-in REST support. GraphQL requires learning a new query language, schema design, resolver patterns, and client-side libraries (Apollo Client, urql), adding 2-4 weeks of ramp-up time for a team. Ongoing maintenance of GraphQL can be more expensive due to schema evolution complexity and the need for query performance monitoring. However, GraphQL reduces frontend development costs by eliminating custom endpoint negotiations between frontend and backend teams.