GraphQL vs. REST APIs: What’s the Difference?

GraphQL and REST are two different styles of application programming interface (API) design commonly used in technology such as mobile apps, web-based apps, and websites. Applications such as Facebook, Instagram, Spotify, and Pinterest rely on these forms of API architecture. APIs facilitate communication between software and remote applications through the Internet.

For example, when you open an application and perform an action such as paying for a food delivery service, the application sends data to a server over the internet. The server then takes the data, processes it, and completes the action. APIs enable this direct communication between applications.

Learn more about GraphQL versus REST APIs, including what you can use them for and the pros and cons of working with each.

What is GraphQL?

GraphQL is an open-source query language for APIs, making APIs faster and more versatile by focusing only on the requested data. The efficiency of GraphQL is possible because, instead of loading data from multiple URLs like other API architectures, GraphQL retrieves all the data required in just one request. Because GraphQL will only return the data you directly request, it’s particularly valuable for mobile applications since some bandwidth limitations are generally present. 

How does GraphQL work?

GraphQL’s unique data retrieval method works by giving you control over the data you receive instead of the server; this way, the results are more predictable. This is possible through four key components of GraphQL—schemas, queries, resolvers, and mutations:

• Schema: Schemas show you exactly what data you can query, what operations the API can use, the relationships between the data, and their characteristics. 

• Query: Queries are requests to the server for data retrieval that contain information on the type of data you want to receive. 

• Resolver: Resolvers can retrieve data from any source and supply the instructions for transforming a query into data.

• Mutation: Mutations help you to update and modify server-side data. You define mutations within the schema to specify the type of change you want to make, such as deleting or creating new data.

What is GraphQL used for?

GraphQL is used in both mobile and web applications to query data efficiently. Products and businesses such as Amazon AWS AppSync and Shopify rely on GraphQL to build their APIs. In addition to querying data, GraphQL can perform data aggregation, taking data from multiple sources and putting it together in one place for improved data analysis. GraphQL can also build dashboard applications that help you monitor real-time data. 

Pros and cons of GraphQL

GraphQL comes with certain pros and cons depending on how you choose to use it. 

Advantages of GraphQL

If you have limited bandwidth or data coming from a range of different sources, GraphQL can be beneficial. You can also integrate GraphQL with other API tools, including REST. Another useful feature of GraphQL is its ability to provide a list of the available data types and minimize miscommunication between the client and server using these defined data types.

Disadvantages of GraphQL

However, one consideration is that if you choose to learn GraphQL, you may face some challenges as it is more complex than other APIs. GraphQL has numerous steps to follow, including creating the schema, defining the variable types, mastering the syntax, and discovering how to retrieve data best. 

What are REST APIs?

A REST (representational state transfer) API is a relatively simple interface that computers use to communicate with one another and gain access to various resources through URLs. This includes content such as algorithms, data, and media. For an interface to be classified as a REST API, it must meet certain guidelines:

• A uniform interface

• Cacheable data

• Stateless operations (no storage of client information between requests)

• Client–server-based architecture

• Hierarchical layers of server types

• Code on demand (can send code from server to client upon request)

How do REST APIs work?

With REST APIs, you must first send a request to the server through HTTP. The server will ensure that you have authentication for the request to go through. Once it authorizes the request, the server will process it before sending a response with the requested information. 

What can you use REST APIs for?

REST APIs are a popular option for mobile and web applications, helping facilitate connections between apps and web services. For example, banking applications use REST APIs to access your account and perform transactions, while social media apps use REST APIs to link with different applications. You can also utilize them for cloud applications, as the stateless nature of REST APIs means they don’t store any client data.

What are the four types of REST APIs?

The four main types of REST API requests you can send to the server are GET, POST, PUT, and DELETE:

- GET: The server returns your requested data

- POST: Grants the server permission to add an entry to a database

- PUT: Updates entries in a database

- DELETE: Enables the server to delete database entries

Pros and cons of REST APIs

Consider the benefits of REST APIs, such as scalability and customization, along with some of their challenges.

Advantages of REST APIs

Implementing REST APIs has several advantages, such as excellent scalability and flexibility. REST’s statelessness allows you to avoid using significant memory, which is advantageous for scaling. REST's flexibility comes from its ability to integrate with other systems and its customizable features, which help you optimize REST for your use case.

Disadvantages of REST APIs

In some specific situations, REST APIs have shortcomings that leave room for other APIs to provide better performance. For example, in applications using real-time data, REST APIs lack the necessary efficiency since you have to send a request to the server to garner a response. 

GraphQL vs. REST APIs

GraphQL and REST APIs are both popular options. They allow you to perform several of the same actions, such as updating, modifying, creating, and deleting data, while also facilitating the transfer of data in client-server models.

Differences do appear between GraphQL versus REST performance, though. In some ways, GraphQL builds on some of the limitations REST experiences, such as performing better in environments that

have limited bandwidth and utilizing data from several sources. This doesn’t necessarily mean GraphQL is superior; it just means GraphQL and REST both have their individual strengths that make them better suited for specific uses. REST outpaces GraphQL for scenarios with less complex data and smaller-scale applications.

Check out our free software developeer and computer science GraphQL and REST APIs resources on Coursera.

Check out the following software developer and computer science resources on Coursera to learn more about GraphQL and REST APIs.

• Take the Skills Assessment: Front-End Development Skill Assessment

• Watch on YouTube: Mastering the Code: Essential Skills Every Software Developer Needs or Software Engineering Roadmap for Beginners (With NO Experience)

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