Update: New to GraphQL? Check out What is GraphQL? before jumping into these details...
REST is an architectural style for creating web services, and GraphQL is a query language designed for APIs. Both enable communication between clients and servers over HTTP, but they approach this task differently.
REST has long been the "go-to" for stateless microservices, whereas GraphQL offers a modern twist with its efficient data-fetching capabilities.
This article walks you through the mechanics of REST and GraphQL, comparing their advantages and downsides when developing web services.
Key Takeaways
- REST and GraphQL both facilitate client-server communications but differ in approach and flexibility.
- GraphQL avoids the overfetching and underfetching problems common in REST APIs.
- Choosing between REST and GraphQL depends on your project's needs and team structure.
What is REST?
REST, short for Representational State Transfer, isn't a protocol but a set of architectural constraints or principles. Services are deemed RESTful when they follow these principles.
In REST, a 'resource' refers to any data entity your service exposes, such as posts, comments, and users in a blog app.
Each resource is accessed via a unique URL, and an HTTP request might look like this:
/users/<id>/postsThe server processes this request and typically returns JSON data:
{
"posts": [
{
"title":"My latest post",
"author":"Sam",
"views":33
},
{
"title":"My other post",
"author":"Sam",
"views":14
},
{
"title":"My first post",
"author":"Sam",
"views":53
}
]
}For a user with a specific <id>, this response returns a JSON array of post objects.
What is GraphQL?
Unlike REST, GraphQL is a strongly typed query language that allows precise data requests through a single endpoint. A schema defines available data types and corresponding queries, enabling fine-grained access to API resources.
A GraphQL query for the same REST data might look like this:
query {
User(id: <id>) {
posts {
title,
author,
views
}
}
}The server would then respond with:
{
"posts": [
{
"title":"My latest post",
"author":"Sam",
"views":33
},
{
"title":"My other post",
"author":"Sam",
"views":14
},
{
"title":"My first post",
"author":"Sam",
"views":53
}
]
}GraphQL achieves the same results but with a single endpoint by leveraging its dynamic query capabilities.
So What's the Point?
Both GraphQL and REST can yield similar responses, but they differ fundamentally in how they manage data retrieval.
Overfetching and Underfetching Data
GraphQL minimizes the common REST issues of overfetching or underfetching. While a typical REST call may overfetch or underfetch data, GraphQL allows you to specify precisely what you need.
Overfetching occurs when more data is returned than necessary, while underfetching happens when not enough data is returned, making additional requests necessary.
While you could modify REST endpoints to mitigate these problems, it often involves more work and coordination.
With GraphQL, you simply update the fields in your queries. For instance, to tackle overfetching, you can ask specifically for only the title:
query {
User(id: <id>) {
posts {
title
}
}
}Or to address underfetching, include more fields:
query {
User(id: <id>) {
posts {
title,
author,
views,
followers
}
}
}One Request to Rule Them All...
GraphQL offers improved client-server interaction by defining a schema, which acts as a clear contract. This approach isolates front-end and back-end teams, allowing UIs to quickly adapt to updated user requirements without needing new endpoints.
GraphQL vs REST: Pros and Cons
Considering whether to use REST or GraphQL requires weighing their respective strengths and weaknesses in light of your project's objectives.
REST Pros:
- Established - REST has been the cornerstone of web services for over two decades.
- Decoupled services - REST is ideal for building standalone microservices that serve multiple applications.
- Caching - REST supports caching effectively, improving performance.
REST Cons
- Redundant requests - Overhead from multiple endpoints can result in too many network requests.
- Versioning hurdles - REST APIs often have to manage versions, complicating updates and maintenance.
- Data inefficiencies - Overfetching and underfetching issues are common.
- Collaboration challenges - Developing front-end applications can be hampered by dependence on available endpoints.
GraphQL Pros
- Defined schema - Offers a clear contract between client and server, promoting cross-team clarity.
- Ease of use - GraphQL's flexibility and ease of getting started can benefit less experienced teams.
- Efficient data retrieval - GraphQL addresses overfetching and underfetching issues.
GraphQL Cons
- Performance risks - Complex, nested queries can hinder performance.
- Schema constraints - Limited by the predefined schema, it can be inflexible in some scenarios.
- Learning curve - While less steep than before, it still takes time to master GraphQL's nuances.
Conclusion
The debate over GraphQL versus REST isn't black and white; both are set to achieve similar goals: efficient client-server communication.
Choosing between the two should consider your organizational needs and development setup. If rapid iteration is crucial, GraphQL shines; for robust, independently deployable services, REST remains a reliable choice.
FAQ
Is GraphQL replacing REST?
No, GraphQL complements REST by offering a flexible solution for certain scenarios. REST is still widely accepted, especially in established systems with well-defined services.
Can REST API caching be implemented in GraphQL?
While native caching isn't a built-in feature of GraphQL, you can implement caching solutions using tools like Apollo Client or server-side caching strategies.
What tool support exists for GraphQL?
GraphQL enjoys robust tool support, including IDEs like GraphQL Playground and clients such as Apollo and Relay, which facilitate development and debugging.
