With the increasing popularity of GraphQL, we, developers are exploring ways to integrate it with existing REST-based backends. GraphQL offers clients the ability to request specific data in a single query, enhancing efficiency and reducing the number of API calls. In this article, we’ll cover key differences between GraphQL and REST payloads, approaches to integrate GraphQL into REST infrastructures, and examples of transforming payloads.
Key Differences Between GraphQL and REST
- Single Endpoint vs. Multiple Endpoints: REST APIs use different endpoints for each resource, while GraphQL provides a single endpoint with customizable queries.
- Customizable Queries vs. Fixed Responses: REST endpoints return pre-defined data, often leading to over-fetching or under-fetching. In contrast, GraphQL allows clients to specify exactly what they need.
- Payload Structure: REST payloads are typically rigid, whereas GraphQL queries allow clients to retrieve nested and related data in a single, structured response.
Techniques for Integrating GraphQL with REST
- GraphQL Layer on Top of REST: Create a GraphQL server layer that interacts with existing REST APIs, transforming client queries into REST calls and aggregating data. This setup preserves the REST backend while offering a GraphQL interface.
- Hybrid GraphQL and REST Endpoints: Serve some data through GraphQL for flexible querying and retain REST for more secure or administrative actions. This allows gradual adoption and offers flexibility without overhauling the backend.
- Federated Approach for Microservices: For complex systems, use a GraphQL gateway to consolidate multiple REST services. Each microservice can have its schema, allowing the gateway to combine responses from different sources into a single payload.
Examples of Transforming REST and GraphQL Payloads
Converting REST to GraphQL Response
For a REST endpoint /users/1 returning:
{
“id”: 1,
“name”: “Alice”,
“email”: “alice@example.com”,
“address”: {
“city”: “Wonderland”,
“zip”: “12345”
}
}
A GraphQL query could fetch only specific fields:
query {
user(id: 1) {
id
name
address {
city
}
}
}
A GraphQL resolver would call the REST API, then filter and structure the response accordingly.
Converting GraphQL Mutation to REST Request
To create a user with a GraphQL mutation:
mutation {
createUser(name: “Alice”, email: “alice@example.com”) {
id
name
}
}
The mutation resolver would translate this into a POST request to the REST API:
const response = await fetch(‘https://myapi.com/users’, {
method: ‘POST’,
headers: { ‘Content-Type’: ‘application/json’ },
body: JSON.stringify({ name, email })
});
Conclusion
Integrating GraphQL with REST provides greater flexibility and efficient data fetching without requiring a full backend rewrite. By layering GraphQL, using hybrid models, or federating requests, developers can optimize API performance and user experience while preserving existing infrastructure stability.
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