When it comes to building APIs, two of the most popular approaches are REST and GraphQL. Both REST and GraphQL are used to enable communication between different applications over the internet through APIs. But what are the key differences between the two, and which approach is right for your project? Let's take a closer look.
What is REST?
REST, or Representational State Transfer, is an architectural style for building APIs that relies on HTTP requests to interact with resources. In a RESTful API, resources are identified by unique URIs (Uniform Resource Identifiers), and clients can make requests to these URIs to retrieve or manipulate the resource.
The REST approach is based on a set of principles that define how the API should be designed. These principles include using standard HTTP methods (such as GET, POST, PUT, and DELETE) to perform operations on resources, using a uniform interface to interact with resources, and relying on stateless communication between client and server.
REST is a popular approach for building APIs because it is simple, flexible, and widely supported by many programming languages and frameworks. However, one downside of REST is that clients must be specific in their requests and sift through all the data that's returned.
Advantages of REST
- Easy to learn and understand
- Well-established and widely used
- Standardized, predictable interface
- Efficient caching mechanisms
Disadvantages of REST
- Limited flexibility in data structures
- Requires multiple requests to retrieve related data
- Can result in data overfetching
- Not suitable for complex queries
What is GraphQL?
GraphQL, on the other hand, is a query language that allows clients to retrieve data from multiple data sources in a single API call. GraphQL was developed by Facebook and has gained popularity due to its ability to provide precise data retrieval.
With GraphQL, clients can specify exactly what data they need and receive only that data in response. This makes it a great choice for complex applications with multiple data sources, as it allows clients to retrieve only the necessary data in a single request.
One key difference between GraphQL and REST is that GraphQL does not rely on URIs to identify resources. Instead, clients send queries to a single endpoint, and the server returns the requested data in a JSON format.
Advantages of GraphQL
- Flexible data structures
- Single request to retrieve all required data
- Efficient handling of complex queries
- Strongly typed schema for data validation
Disadvantages of GraphQL
- Requires more effort to learn and understand
- Can suffer from performance issues due to complex queries
- Requires additional effort to implement caching
REST vs. GraphQL
In GraphQL, there is a crucial element known as a schema, which serves as a blueprint defining all the potential data that clients can request through a service. A query, on the other hand, is a request for data that adheres to the structure laid out in the schema. When a query is submitted, a resolver is invoked to retrieve the requested data, which may entail gathering data from various sources and assembling it to match the query structure. Lastly, we have mutations, which are responsible for altering data on the server. In CRUD terminology, queries are analogous to "reads," while mutations take care of "creates," "updates," and "deletes."
Now, let's turn our attention to REST. In REST, resources are the core building blocks, each with a unique identifier known as a URI. Clients may request a response by using HTTP methods such as GET, PUT, POST, and DELETE to access these resources. The server responds with a representation of the resource in JSON or XML format. REST APIs also allow clients to filter, sort, and paginate data using query parameters.
|Data Fetching||Data is fetched using specific endpoints.||Data is fetched using a single endpoint, reducing the number of requests needed to retrieve data.|
|Query Complexity||Suited for simple queries and CRUD operations.||Suited for more complex queries with nested fields and multiple data sources.|
|Response Size||Response size can be larger due to the inclusion of unnecessary data.||Response size is smaller because clients can request only the data they need.|
|Caching||Can be easily cached using HTTP caching mechanisms.||Caching requires more effort due to the complexity of the queries.|
|Schema Definition||No formal schema definition is required.||A formal schema definition is required, providing more structure to the API.|
|Versioning||Requires versioning when making changes to the API.||Changes can be made without requiring versioning, reducing API maintenance overhead.|
|Security||Uses standard HTTP security mechanisms like SSL and OAuth.||Provides additional security features like query validation and authorization.|
|Tooling||Has a wide variety of tooling options available.||Has fewer tooling options available, but is gaining popularity and tooling support.|
|Learning Curve||Easy to learn and implement.||May have a steeper learning curve due to the formal schema definition and more complex queries.|
|Compatibility||Works well with existing API management tools.||Can be introduced on top of an existing Rest API and can work with existing API management tools.|
Despite these similarities, there are significant differences between the two technologies. When a REST API is queried, it returns the full data set for that resource. In contrast, GraphQL is a query language specification and a set of tools that enable clients to interact with a single endpoint. REST APIs frequently require multiple requests to retrieve related data, while GraphQL can collect all of the data in a single request using a complex query that adheres to the schema. As a result, clients receive just what they requested, without any unnecessary over-fetching.
Rest APIs are a familiar concept for most developers, while GraphQL may present a bit of a learning curve for some. Rest APIs are particularly well-suited for applications that require simple CRUD operations. For example, an e-commerce website might use a rest API to enable customers to browse products, add items to their cart, and complete orders. In this case, the API would use the HTTP methods, such as GET, PUT, POST, and DELETE, to manipulate data such as products, orders, and customer information.
REST follows a client-server architecture where the client makes requests to the server, and the server responds with resources. REST uses HTTP verbs to perform CRUD operations on resources.
GraphQL, on the other hand, follows a client-driven architecture where the client specifies the structure of the data they need, and the server responds with the requested data.
RESTful APIs are known for their high performance, as they use standard HTTP protocols for communication. RESTful APIs can also be easily cached, making them faster and more efficient.
GraphQL, on the other hand, can suffer from performance issues due to the complexity of the queries. As the client can request any data they need, GraphQL queries can become very complex, resulting in slower response times.
In RESTful APIs, the client needs to make multiple requests to retrieve related data. This can result in complex client-side logic to manage the relationships between the resources.
In GraphQL, the client specifies the required data, and the server returns only that data, including any related data. This simplifies the client-side logic and reduces the number of requests required.
Data Over-fetching and Under-fetching
In RESTful APIs, the client retrieves an entire resource, even if they only need a part of it. This is known as data over-fetching and can result in unnecessary network usage and slower response times.
In GraphQL, the client can request only the required data, which eliminates data over-fetching. However, if the client requests too little data, it can result in data under-fetching, which requires additional requests to retrieve the missing data.
RESTful APIs are easily cached, as the standard HTTP protocols provide built-in caching mechanisms. This makes RESTful APIs faster and more efficient.
GraphQL does not have built-in caching mechanisms, as the queries can be very complex and dynamic. Caching GraphQL queries requires more effort and may not be as efficient as caching RESTful APIs.
What I mean by this is that GraphQL is particularly useful when dealing with nested fields or multiple data sources. For example, a company that provides a suite of financial planning tools for its clients might require data from multiple sources such as bank transactions, investment portfolios, and credit scores. With GraphQL, the company can build a single API endpoint that allows clients to query all of the data in a single request. Clients can simply specify the data they need, and the server will use a set of resolvers to fetch the necessary data from each source and assemble it into a response that matches the query structure.
Rest and GraphQL can also work together as GraphQL does not dictate a specific application architecture. It can be introduced on top of an existing Rest API and can work with existing API management tools. Both Rest and GraphQL have their unique strengths and quirks, and understanding their similarities and differences will help you choose the right tool for the job.
Can you use both REST and GraphQL in the same application?
Yes, it is possible to use both REST and GraphQL in the same application, depending on the specific requirements of the application.
Is GraphQL faster than REST?
GraphQL can suffer from performance issues due to the complexity of the queries, while RESTful APIs are known for their high performance. However, GraphQL can be faster in some cases where the client needs to retrieve a large amount of related data in a single request.
Can GraphQL replace REST?
GraphQL and REST have different strengths and weaknesses, and the choice between them depends on the specific requirements of the application. It is not necessarily a case of one replacing the other.
Is GraphQL more secure than REST?
Both GraphQL and REST can be secured using standard security mechanisms, such as authentication and authorization. The security of the API depends on how it is implemented and configured.
What are some popular companies that use GraphQL?
Some popular companies that use GraphQL include Facebook, GitHub, and Shopify.