Core Differences Between GraphQL and REST API
GraphQL is a query language and runtime environment for APIs. Here are the core differences between GraphQL and REST API:
1. Data Fetching Approach
- REST: Clients need to access multiple endpoints to fetch related data, potentially leading to over-fetching or under-fetching
- GraphQL: Clients can specify exactly the data fields they need in a single request, avoiding over-fetching and under-fetching
2. Endpoint Design
- REST: Resource-based endpoint design, each resource has its own URL
- GraphQL: Single endpoint, all requests are sent to the same URL
3. Versioning
- REST: Typically requires versioning (e.g., /api/v1/users)
- GraphQL: Evolves through Schema, no versioning needed, can deprecate fields without breaking existing clients
4. Request Methods
- REST: Uses standard HTTP methods (GET, POST, PUT, DELETE)
- GraphQL: Uses POST method to send queries, mutations, and subscriptions
5. Response Format
- REST: Response format is determined by the server
- GraphQL: Response format is determined by the client's query
6. Caching Strategy
- REST: Can leverage HTTP caching mechanisms
- GraphQL: Requires implementing custom caching strategies (e.g., Apollo Client cache)
7. Real-time Data
- REST: Usually requires polling or using WebSocket
- GraphQL: Natively supports subscriptions for real-time data updates
8. Error Handling
- REST: Uses HTTP status codes to indicate errors
- GraphQL: Includes errors field in the response body, HTTP status code is usually 200
9. Type System
- REST: Typically uses OpenAPI/Swagger for documentation, but not strongly typed
- GraphQL: Built-in strong type system, Schema defines all available types and operations
10. Documentation
- REST: Requires manual maintenance of API documentation
- GraphQL: Schema itself is documentation, can be automatically generated through tools
Use Cases
GraphQL is suitable for:
- Applications that need to fetch complex nested data from multiple data sources
- Mobile applications that need to reduce network requests and data transfer
- Multiple clients with flexible data requirements
- Fast-iterating products that need frequent API adjustments
REST is suitable for:
- Simple CRUD operations
- Scenarios that need to leverage HTTP caching
- Public APIs that need to be simple and easy to use
- Scenarios where the team is unfamiliar with GraphQL