REST API is an architectural concept for exchanging data between applications. On the other hand, GraphQL is a specification, an API query language and a set of tools. GraphQL runs on a single address using HTTP.
In addition, the development of REST was more focused on creating new APIs. GraphQL developers, on the other hand, focused on API performance and flexibility.
Following are some other differences.
Client-side query
The following describes how a REST request works.
HTTP verbs that define the action
A URL that defines the resource where the HTTP command should be executed
Parameters and values to analyze if you want to create or modify an object in an existing server resource
For example, you use a GET request to retrieve read-only data from a resource, a POST to add a new resource record, or a PUT to update a resource.
In contrast, GraphQL queries use the following:
- A query to retrieve read-only data
- Data modification function
- Subscribe to receive event-based or streaming data updates
- The data format describes how the server should return the data, including objects and fields that match the server-side schema. You can also enter new data. Internally, GraphQL sends each client request as an HTTP POST request.
Server-side schema
GraphQL uses a server-side schema to define data and data services, which is different from the REST API.
The schema, written in the GraphQL schema definition language, contains the following information:
Object types and fields belonging to each object
Server-side resolver functions that define the operation for each field
The schema clearly defines the types that describe all the data available in the system and how clients can access or modify that data.
On the other hand, server-side schema is not required for REST APIs. But you can define it additionally for efficient API design, documentation, and client development.
Version control
As APIs evolve, their data structures and operations may change. Clients unaware of these changes can crash their systems or make unknown errors.
To address this issue, REST APIs often use a version detection function in the URL, such as https://example.com/api/v1/person/12341. However, version control is not mandatory and can cause errors.
For GraphQL, backwards compatibility of the API is required. Thus, deleted fields return an error message and fields with an outdated tag return a warning.
Error handling
GraphQL is a strictly typed API architecture, so it requires a detailed description of the data, its structure, and data operations in the schema. Because of the level of schema detail, the system can automatically detect query errors and provide useful error messages.
REST APIs are loosely typed and you must build error handling into the appropriate code. For example, if a PUT request analyzes a numeric value as text rather than an integer, the system does not automatically identify the error.