GraphQL vs REST: When to Use Which

REST (Representational State Transfer) has been the dominant API architecture for over two decades. Its simplicity and alignment with HTTP make it intuitive for developers familiar with web fundamentals. Major platforms like Twitter, Stripe, and most enterprise systems built their APIs on REST principles.

REST's strength lies in its conceptual simplicity: resources have URLs, HTTP verbs define actions, and status codes communicate results. This maps naturally to CRUD operations and makes APIs self-documenting. Tools like Postman and Swagger provide excellent REST support.

• Resource-based URLs (GET /users/123)
• HTTP verbs for actions (GET, POST, PUT, DELETE)
• Stateless request/response model
• JSON or XML data format
• Standard HTTP status codes

The main limitation is over-fetching and under-fetching. A mobile app might need only a user's name and avatar, but the REST endpoint returns 50 fields. Conversely, displaying a user's posts requires additional API calls, creating the N+1 query problem.

GraphQL, developed by Facebook in 2012 and open-sourced in 2015, takes a fundamentally different approach. Instead of multiple endpoints, GraphQL provides a single endpoint with a powerful query language that lets clients request exactly the data they need.

The core innovation is the schema-driven approach. Developers define a type system that describes available data and relationships. Clients then write queries that traverse this graph, fetching related data in a single request. This eliminates over-fetching and reduces round trips.

• Single endpoint for all operations
• Client-specified data requirements
• Strongly typed schema
• Built-in introspection and documentation
• Real-time subscriptions
• Schema evolution without versioning

The complexity comes from the schema layer. Teams need to design resolvers, handle N+1 queries with DataLoader patterns, and implement proper authorization at the field level. The learning curve is steeper, especially for teams new to schema-first development.

Performance depends heavily on use case complexity. For simple operations, REST often wins due to lower overhead and excellent HTTP caching. For complex operations involving multiple related resources, GraphQL typically performs better by eliminating round trips.

REST excels when fetching single resources or when the client needs exactly what the endpoint provides. HTTP caching works seamlessly - CDNs, browser caches, and reverse proxies all understand REST responses. This makes REST ideal for public APIs serving diverse clients.

GraphQL shines when clients have specific data requirements. A mobile app loading a user profile might need name, avatar, recent posts, and follower count - traditionally requiring 3-4 REST calls. GraphQL fetches this in one optimized query, reducing latency especially on slow connections.

The complexity difference between REST and GraphQL extends beyond initial learning. REST's simplicity means faster onboarding for new team members and easier debugging when things go wrong. GraphQL's power comes with infrastructure complexity that teams must manage.

REST development follows familiar patterns. Most backend developers can build REST endpoints quickly using frameworks like Express.js, Django REST, or Spring Boot. Error handling is straightforward with HTTP status codes, and debugging tools are mature.

GraphQL requires schema design skills, resolver optimization, and understanding of concepts like DataLoader for N+1 prevention. Teams often need dedicated GraphQL experts initially. However, the investment pays off for complex applications with multiple client types.

The choice between REST and GraphQL often comes down to team experience, application complexity, and client diversity. Neither is universally better - each excels in specific contexts.

REST remains the pragmatic choice for most traditional web applications, especially those with server-side rendering or simple client requirements. It's also preferred for public APIs where simplicity and broad compatibility matter more than optimization.

GraphQL makes sense for complex applications with multiple client types (web, mobile, internal tools) that need different data subsets. Companies like GitHub, Shopify, and Facebook use GraphQL to serve diverse client needs efficiently.