GraphQL vs REST

 GraphQL 

GraphQL is an application layer server-side technology which is developed by Facebook for executing queries with existing data. GraphQL can optimize RESTful API calls. It gives a declarative way of fetching and updating your data.

GraphQL helps you to load data from server to client. It enables programmers to choose the types of requests they want to make.

REST

REST is a software architectural style that defines a set of constraints for creating web services. It is designed specifically for working with media components, files, or hardware device. The full form of REST is Representational State Transfer.

=========================================================

Here is the important difference between GraphQL and REST.

GraphQL	REST
GraphQL is an application layer server-side technology which is developed by Facebook for executing queries with existing data.	REST is a software architectural style that defines a set of constraints for creating Web services.
It follows client-driven architecture.	It follows server-driven architecture.
GraphQL can be organized in terms of a schema.	REST can be arranged in terms of endpoints.
GraphQL is a growing community.	REST is a large community.
The development speed in GraphQL is fast.	The development speed in REST is Slow.
The learning curve in GraphQL is difficult.	The learning curve in REST is moderate.
The identity is separated from how you fetch it.	The endpoint you call in REST is the identity of an object.
In GraphQL, the server determines available resources.	The shape and size of the resource are determined by the server in REST.
GraphQL provides high consistency across all platforms.	It is hard to get consistency across all platforms.
The message format for GraphQL mutations should be a string.	The message format for REST mutations can be anything.
It is strongly typed.	It is weakly typed.
GraphQL API endpoints are single.	REST API endpoints are multiple.
It uses metadata for query validation.	It does not have machine-readable metadata cacheable.
Provides consistent and high-quality UX across all operating systems.	It is difficult to get consistency across all operating systems.
Partners of GraphQL require API customization.	It offers flexible public API that can easily enable new applications.

Advantages of GraphQL

Here are the important pros/benefits of GraphQL:

• It provides declarative query language, which is not imperative.
• It is hierarchical and product-centric.
• GraphQL is strongly typed. It means queries are executed within the context of a particular system.
• Queries in GraphQL are encoded in the client, not in the server.
• It has all the features of the application layer of the OSI model.
• GraphQL provides a human-readable query.
• In GraphQL, it is easy to deal with many databases.
• You can fetch data with a single API call.
• It helps you with query batching and caching.
• Tailoring requests to your needs.
• It helps you to discover the schema in the appropriate format.
• GraphQL automatically keeps documentation in sync with API changes.
• API evolution is possible without versioning.
• It can be used for rapid application prototyping.
• GraphQL fields can be shared to a higher component level for reuse.
• It allows you to select which functions to expose and how they work.

Advantages of REST

Here are the important pros/benefits of REST:

• It enables you to scale software without any difficulty.
• You can perform migration from one server to another with ease.
• The protocol becomes easy for developments across different projects.
• REST API offers the opportunity to try various project environments while developing it.
• REST is very easy to build and adapt.
• You can create process instances explicitly.
• The client machine does not need routing information.
• Developers can build API that can meet a user-specific need.

Application of GraphQL:

Here are the important applications of using GraphQL:

• It provides relay and other client frameworks.
• GraphQL helps you to improve the performance of the mobile app.
• It can be used when the client application has to specify which fields are needed in a long query format.
• GraphQL can be fully utilized when you have to add functionality to your old or existing API.
• It is used when you have to simplify complex API.
• Mix and mash facade pattern, which is commonly used in object-oriented programming.
• It can be used when you have to aggregate data from more than one place into one convenient API.
• You can use GraphQL as an abstraction on an existing API to specify a response structure based on user needs.

Application of REST

Here are the important applications of using REST:

• REST is used in heterogeneous languages and environments.
• It enables web applications that are built on various programming languages to communicate with each other.
• With the help of REST, these web applications can reside on different environments, some could be on Windows, and others could be on Linux.
• Make UI portable across multiple platforms.
• Obtain a uniform interface.
• Layered system in which architecture is made of hierarchical layers.

Disadvantages of GraphQL

Here are cons/drawbacks for using GraphQL:

• Lack of resources on the backend part.
• Missing design pattern for a complex app.
• Performance issues with complex queries.
• Overkill for small applications.
• It does not base on the HTTP caching methods that enable storing request content.
• You need to learn the GraphQL Schema Definition Language before you implement GraphQL strategies.
• GraphQL uses a single endpoint instead of following the HTTP caching.
• It is not a good solution for simple applications as it can add complexity.

Disadvantages of REST

Here are cons/drawbacks for using REST:

• REST does not maintain states of a previous interaction between client and server.
• If you have to retrieve any data from two endpoints, you need to send two separate requests to API.
• There is no way to get limited fields.
• Manipulating nested resources is not possible.
• Poor data searching facility.
• Query validation is not available.
• It does not handle API additions, deprecations, and changes.
• There is no tooling or framework guidance.

What is Better?

GraphQL has many advantages over REST. GraphQL is faster than REST because you can easily pick the fields you have to query. GraphQL provides a better learning curve as compared to REST.

In general, selecting GraphQL or REST is a difficult task because both are good in their way. Moreover, there is also similarities between them like the endpoints in REST API and the list of fields which is there in GraphQL.