GraphQL vs REST: What are the differences?

1. Data Fetching: In GraphQL, the client can specify exactly what data it needs, allowing for fetching of only required data in a single request, reducing over-fetching. In contrast, REST endpoints return fixed data structures that may include excess or insufficient information, resulting in over-fetching or under-fetching. 2. Overhead: REST endpoints often require multiple requests to fetch related resources, leading to additional overhead in terms of network requests and data processing. On the other hand, GraphQL allows for fetching all necessary resources in a single request, reducing network overhead and improving performance. 3. Versioning: GraphQL does not require versioning of APIs as clients can request only the fields they need, and schema changes can be managed without impacting existing queries. In REST, versioning is important to maintain backward compatibility for clients, requiring explicit versioning in endpoints or headers. 4. Response structure: REST APIs have predefined response structures determined by the server, leading to potential issues when clients do not need all the data. GraphQL, on the other hand, allows clients to request data in the structure they desire, enabling flexible and precise data retrieval. 5. Caching: REST APIs rely on standard HTTP caching mechanisms like ETag or Last-Modified headers for caching responses, which can be complex to manage. GraphQL provides a built-in caching layer that allows for more granular control over data caching, improving efficiency and reducing redundant data fetches. 6. Documentation: In GraphQL, the schema serves as the source of truth for the API, providing detailed documentation and enabling introspection capabilities for clients to explore available data and operations. In REST, documentation is typically external to the API, leading to potential inconsistencies between the documentation and the actual API implementation.

In Summary, GraphQL and REST differ in data fetching efficiency, network overhead, versioning requirements, response structure flexibility, caching mechanisms, and documentation integration.