GraphQL vs. REST API - what are the advantages

To enable web applications to exchange information and data with other local or remote programs, they use an Application Programming Interface (API). This is a universal interface implemented on one side, defining the structure and type of communication while waiting for connections from outside. In addition to proprietary solutions, there are also general standards for the format of contact and data transmission, aiming to define a uniform standard independent of a specific application. Two of the most popular and widely used approaches are GraphQL and Representional State Transfer (REST).

What lies behind REST and GraphQL?

Both GraphQL and REST serve to provide a basic structure for a universally understandable and usable API. However, they are not just specific interfaces with a fixed and standardized structure and commands, but fundamentally two different concepts or architectures, each with their own advantages and disadvantages. Specifically, REST consciously avoids defining a uniform and universal interface, instead primarily describing a method for communication between programs or machines (Machine-to-Machine or M2M).

In contrast, GraphQL includes a combination of an SQL-like query language, a suitable runtime environment for different programming languages, and a type system for describing the API.

What are the characteristics and advantages of REST?

The development and name of REST stem from the dissertation of the US computer scientist Roy Thomas Fielding, who played a crucial role in the specification of HTTP as a data transfer protocol. In his work, he develops REST as a set of guidelines to be followed for communication, such as an API. These include:

• Addressability of each resource through a globally unique address in the form of a URL
• Standardisation of the interface, for example through the POST and GET methods in HTTP
• Simple and clear structure with servers and clients establishing connections
• Messages containing all necessary data for understanding (statelessness)
• Representation of resources in different languages such as HTML, JSON, or XML
• Provision by the server through simple URLs without additional information

From this approach, numerous advantages emerge, while the disadvantages remain manageable. The advantages include:

• Web servers like NGINX or Apache as interfaces to the API
• Use of rarely blocked ports for communication
• Clear and simple identification of the API
• Use of HTTP methods like POST and GET for communication
• Independence from platform, operating system, and software
• Support for mobile clients and desktops
• Excellent scalability and performance

What are the distinguishing features of GraphQL?

Behind GraphQL is Facebook, which initially developed the standard for an efficient API for internal use in 2012 and released it for general use as open source in 2015. It is a combination of a runtime environment with libraries for key programming languages such as Java, JavaScript, PHP, Python, or Ruby, and a database with SQL-like syntax. Querying the validity of requests is possible through the type system, which can identify and authenticate a user due to its unique structure and specific entries. The advantages of GraphQL include:

• Easy integration into own code through libraries
• Compatibility with various programming languages and frameworks
• Complete runtime environment available in open source
• Direct exchange of information in a database format
• Flexible adaptation of the API easily achievable
• Independence from a web server or other IT infrastructure

Conclusion: Which API is suitable for a specific project?

Both variants have specific advantages, but due to their flexibility and customisation capabilities, they have few disadvantages. The choice of which approach to use often depends on personal preference rather than specific limitations. An exception is stand-alone applications that exclusively use their API locally: in this case, GraphSQL shows certain advantages if the operation of additional software such as a web server is to be avoided.

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