GraphQL vs. Rest API in headless eCommerce applications

If you’re considering choosing the right tool to communicate between your application and the server, you’ve surely come across the term API.

What Is an API (Application Programming Interface)?

An API is a set of rules and protocols that enable effective communication between different applications. This mechanism precisely defines how different software components should work together, thus facilitating integration between them. In the context of websites, APIs are often used for communication between frontend and backend

There are a variety of different types of application programming interfaces, and among them there are two particularly common examples mentioned in the title: the GraphQL and REST APIs.

What Are the Highlighted Technologies and Where Did They Come From?

REST API, as well as GraphQL, are publicly available styles of software architecture. Their main purpose is to seamlessly exchange data between the applications and integrated platforms used and the server.

They provide client applications with the ability to use and manipulate server resources using common HTTP methods such as GET, POST, PUT and DELETE. With them, it is possible to send a variety of requests.

REST (Representational State Transfer) API

In the REST architecture (sometimes called the RESTful API), data is treated as a resource, and each resource is identified by a unique URI (Uniform Resource Identifier). For example, for a collection of users, the URI could look like this: /users. Resources, on the other hand, are represented in a form that can be transferred between client and server. The most commonly used representation format is JSON.

REST defines some basic operations that can be performed on resources. These are mostly CRUD (Create, Read, Update, Delete) operations, mapped to standard HTTP methods: POST, GET, PUT, DELETE.

REST API Advantages:

• Simplicity: REST API is easy to understand and use for both developers and customers.
• Compatibility: REST API can be used in conjunction with any technology and in a variety of development environments.
• Ease of Testing: The REST API is easy to test because operations are typically based on standard HTTP methods, making it easy to use API testing tools.
• Ease of Caching: Because of explicit resource identification and clear operations, query results can be easily cached.
• Statelessness: The lack of server-side sessions makes it easy to scale and manage multiple requests. Once a request is received, the server is not required to store any information related to that particular request.

Disadvantages of REST APIs:

• Over-communication: When querying large amounts of data, REST can lead to excessive information transfer, which can significantly affect application performance.
• Lack of Built-in Security Mechanisms: REST APIs do not provide built-in security mechanisms, which means developers must take care of aspects such as authentication and authorization themselves.
• Insufficient for Certain Applications: For some more advanced cases, such as streaming data, REST may be less suitable than other architectures.

Example usage:

When creating a clear and effective structure for an eCommerce application, such as a marketplace and a dedicated seller (vendor) subpage, we need a variety of information, including:

• vendor data,
• the products of the vendor in question,
• customer reviews,
• order information.

In this case, it would be necessary to create several endpoints:

• /user/id to get data about the seller,
• /user/id/products to get a list of products of a given user,
• /user/id/reviews for reviews,
• /user/id/orders to get information about completed orders, such as their quantity.

fetch('/user/1234')
 .then(response => response.json())
 .then(data => {
   // Handling the data returned from the API
   console.log(data);
 })
 .catch(error => {
   // Error handling
   console.error('Error while downloading data:', error);
 });

However, in either case you get a full set of information, even the information you don’t currently need. It is then possible to transform the API to match the requirements of a particular feature or subpage, but in the case of expansion or changes in the application’s assumptions, it would take longer to adapt the API for each request. This would limit the speed of making changes to the application on the frontend side.

GraphQL

GraphQL is a common alternative to REST-based APIs, especially for headless eCommerce solutions. What is still distinctive about this solution is that GraphQL always uses only one endpoint.

GraphQL Advantages:

• Compatibility and Flexibility: GraphQL can also be used in conjunction with any technology, just like REST API.
• Performance Optimization: GraphQL minimizes irrelevant and inefficient information transfer by fetching only the necessary data through parallel requests — improving network performance and the overall user experience — in other words, using GraphQL schemas we get only what we need.
• Easy Scalability: When developing or modifying a frontend application, you don’t have to worry about handling API queries. All you need to do is add or slightly modify the query.
• Code Reduction: Reduces code duplication, which makes it easier to maintain, streamlines the development process and guarantees uniformity.

Disadvantages of GraphQL:

• Caching: One endpoint makes it very difficult to implement a cache in the browser to avoid re-fetching the same data.
• Buffering Issues: Some buffering difficulties may arise with GraphQL, especially for headless content management systems (CMS) or applications that handle large and complex queries.
• Error Handling: Unfortunately, with this method, you have to look at the entire response to find out where and why the error occurred, not like with the REST API.

Example usage:

Referring to the same example as in the previous method, using GraphQL it would be sufficient to use only one endpoint. The query could then look as follows:

query {
 user(id: "1234") {
   email
   firstName
   lastName
   products {
     id
     name
     price
   }
   reviews {
     id
     title
     content
   }
   orders {
     count
   }
 }
}

We would get information about a given user, his products, reviews, etc. with only the required parameters.

Conclusion: In What Cases Will the Described Methods Work?

GraphQL will work well in an application that requires varied data on individual pages and complex query capabilities.

However, in the case of handling large amounts of data, it may be more advantageous to use a REST API. This is because sometimes complex GraphQL queries can introduce latency, especially when compared to querying several REST API endpoints. In addition, the ease, statelessness and stable data management, as well as the speed of REST API development, are undeniable advantages, making them an attractive choice, especially for smaller applications.

In conclusion, GraphQL and REST APIs are two different methods of building programming interfaces, and each has its advantages and disadvantages. GraphQL gives more flexibility in searching and retrieving data, while REST is more straightforward and facilitates caching. The key, however, is to evaluate specific requirements and challenges to determine which method is the right choice for our headless eCommerce application. Nevertheless, keep in mind that the coexistence of both solutions in a project is not out of the question! 🤓