Introduction

As developers continue to build more complex applications, the need for efficient data processing and retrieval becomes paramount. GraphQL and REST are two popular approaches to building APIs, each with its strengths and weaknesses. In this article, we will dive into the details of both and help you make an informed decision about which to use for your API.

What are GraphQL and REST?

REST (Representational State Transfer)

REST is an architectural style for designing networked applications. It uses a stateless client-server communication model, where each request from the client to the server must contain all the information needed to understand and process the request.

GraphQL

GraphQL is a query language for APIs and a runtime for executing those queries with your existing data. It was developed by Facebook in 2015 to address some of the limitations of REST.

Key differences

Flexibility in data retrieval

REST

With REST, if you want to retrieve information about a user and their posts, you must hit at least two endpoints.

REST - Multiple endpoints 
// First call for the user
GET /api/users/1

// Second call for the user's posts
GET /api/users/1/posts

GraphQL

By contrast, with GraphQL, you can retrieve the same information in a single request by building a query that specifies exactly the data you need.

GraphQL - Single query 
query {
  user(id: 1) {
    name
    email
    posts {
      title
      content
    }
  }
}

Over-fetching and under-fetching

Over-fetching with REST

With REST, endpoints return a fixed data structure. If your application only needs part of the data, you are still forced to retrieve everything.

Precision with GraphQL

With GraphQL, you specify exactly the data you need, which can prevent over-fetching and under-fetching.

API versioning

REST

With REST, when the data structure changes, you often need to create a new version of the API (v1, v2, v3...).

REST - Versioning 
GET /api/v1/users/1
GET /api/v2/users/1  // New version with different fields

GraphQL

With GraphQL, the client specifies the shape of the data, so even if new fields are added on the server, existing queries do not break.

Comparison table

Criteria REST GraphQL
Flexibility Fixed endpoints Flexible queries
Over-fetching Frequent Avoided
Versioning Required (v1, v2...) Not required
Learning curve Low Medium
Caching Native HTTP More complex

Conclusion

In summary, GraphQL and REST each have their own strengths and weaknesses. GraphQL offers a lot of flexibility and efficiency in data retrieval, preventing problems of over-fetching and under-fetching. It also eliminates the need for API versioning, which can lead to easier maintenance and scalability.

On the other hand, REST is a mature technology with broad support, and its stateless nature can make it a bit easier to understand and use, especially for simpler use cases.

When choosing between REST and GraphQL, it is important to consider the specific needs and constraints of your project. If your application needs to retrieve complex data with multiple relationships, or if you want to give your clients more control over the data they retrieve, GraphQL might be the best choice. However, if you are building a simpler application, or if your team is already familiar with REST, then REST might be a more appropriate choice.

References

GraphQL REST API Backend