GraphQL vs REST

What Is REST?

REST (Representational State Transfer) is a popular way to build web applications that communicate with each other. It enables programs, like your phone app or a website, to get and send information to a server using the standard web communication rules (HTTP).

REST establishes the basic rules for communication among different parts of a web system. REST is stateless, meaning that every request that goes from a client to a server is completely independent of all prior requests; the server does not need to remember any prior state, as the request contains all the information it needs.

Further, there is client/server separation, which separates responsibilities: the client is responsible for the presentation (the things you see and interact with), and the server is responsible for creating and modifying the data and logic. REST is also a uniform interface. Finally, REST identifies its resources; it treats everything as a unique "resource."

What is GraphQL

GraphQL, a query language and runtime for APIs that was created by Facebook, is designed to allow clients to receive data from a single endpoint, requesting only the data they need. This is more flexible than REST APIs. GraphQL is schema-based, defining the types and relationships of data.

It builds a kind of contract about what to ask for. All client requests are made to the single GraphQL endpoint. It will allow clients to make flexible queries that specify the structure of the data, as opposed to being limited to an API defined structure. 

GraphQL vs REST API: A Comparative Overview

1. Data Fetching

REST defines a primitive set of rules for resource relationship communication within web systems. REST is stateless, meaning that every request from a client to a server is completely independent of any previous request; the server will not need to remember any previous state, because everything it needs is included in the request.  Further, they have client/server separation, which separates responsibilities:

The client is responsible for presentation (the things that you can see and touch), and the server is responsible for creating and modifying the data and logic.  REST also contains a uniform interface. Finally, REST identifies its resources; it treats everything as a unique "resource."

2. Versioning

Generally, REST handles versioning openly and explicitly for evolving APIs, often explicitly as part of the URL (e.g., /api/v1/users, /api/v2/users), which leads to service providers maintaining multiple REST API versions, increasing complexity to the consumer.

GraphQL allows for evolution simply in its schema; new fields can be added, and old fields can be deprecated rather than taking the approach of creating a new version. Creation is less disruptive to evolving an API.

3. Caching

The same goes for data caching: REST has a robust and inherent HTTP caching mechanism on the web that makes it relatively easier to implement caching strategies at multiple levels (meaning browser, proxy, and server). Generally speaking, GraphQL will require custom caching strategies because all requests go to (and through) a single endpoint, and requests are incredibly dynamic. That said, caching will likely need to be at a more granular level, i.e. custom resolver-level caching on the server, or more sophisticated client-side caching strategies.

4. Performance Differences

Depending on the complexity of the data retrieval, the performance differences between REST and GraphQL will matter. Generally speaking, REST performs better for simple, simple requests of a single resource -- because it is directly tied to HTTP methods and is cacheable.

But, with more complex data retrieval needs, it is consistently better to use GraphQL since it allows the client to retrieve an arbitrary set of complex, nested, or deeply related data in a single request -- without needing to do multiple round trips required by the REST API to collect all of the related pieces of information. Thus, there are a considerable savings in network latency for complex queries.

5. Scalability

Both of these structures can scale, just in different ways. REST scales well for APIs with basic resource-based interactions, low computing costs, statelessness, as well as strong caching support for horizontal scaling.

On the other hand, GraphQL scales better for APIs with a lot of complex data relationships and quickly changing frontend data needs. The ability to fetch just the right data in one request, plus scheme-changing flexibility, allows for greater efficiency with dynamically shaped applications versus a required, excessive API alteration on the backend and frontend changes on client side.

When to Use GraphQL vs REST

Decision Tree for Choosing Between GraphQL and REST:

Are your data requirements simple and stable?

└─ Yes → Use REST

└─ No → Do you need to aggregate data from multiple sources?

└─ Yes → Use GraphQL

└─ No → Is frontend frequently changing?

└─ Yes → Use GraphQL

└─ No → Use REST

REST or GraphQL: When to Choose Each?

REST is great in cases with fairly simple Create, Reads, Updates, Delete (CRUD) functionality, and is preferable when resources are limited on the client-side (such as mobile).

GraphQL is a more reasonable choice in cases which require manipulation of complex data or information. GraphQL may also work well with mobile applications.

In short: REST is preferable for simple, stable APIs and GraphQL is a good choice for more complex applications.

A Framework to Choose Between GraphQL and Rest

Ask these questions to yourself before deciding on GraphQL and REST. 

1. How complex are your data relationships? 

If your data models are deeply intertwined with numerous connections between different entities (e.g., users, posts, comments, authors, tags), GraphQL's ability to traverse these relationships in a single query becomes highly advantageous. For simpler, flatter data structures, REST often suffices.

2. How often do frontend requirements change? 

In situations where frontend features and data display requirements are rapidly changing, GraphQL client-driven query allows frontend teams the ability to adapt without continuous updates from backend teams. Because REST operates on fixed endpoints, more backend changes are usually required to accommodate new UI requirements.

3. Do you need to aggregate data from multiple sources?

If your API needs to consolidate data from various microservices, databases, or external APIs into a unified response, GraphQL excels as an aggregation layer, simplifying client-side data orchestration. REST would typically require clients to make multiple calls to different services.

4. Is bandwidth a concern for your clients? 

For mobile application or areas where network connectivity is limited, reducing the amount of data transferred is essential. GraphQL's exact nature of data fetching is the solution to this, as it avoids over-fetching, in other words it only sends the data needed over the wire. REST has over-fetching potential in this regard.

5. How important is HTTP caching? 

When your application is fully dependent on built-in HTTP caching for performance and scalability (e.g., caching static resources or data that rarely changes), REST compliant with standard rest offers a key benefit. While GraphQL can be cachable, applications often need to create custom more complex caching layer.

Evaluation Checklist

Use this checklist as a quick reference when evaluating which API style is more suitable:

1. Simple, stable data model → Choose RESTful API
2. Complex, evolving data needs → Choose GraphQL API
3. Need for precise data fetching (avoid over/under-fetching) → Choose GraphQL
4. Heavy reliance on HTTP caching → Choose REST API
5. Multiple data sources to aggregate → Choose GraphQL

Conclusion

Choosing between REST and GraphQL depends on your project's needs. REST is great for simple, stable APIs, benefiting from standard web caching. GraphQL, however, shines with complex data, changing app needs, and mobile efficiency, letting you get exactly what you want. Pick the one that best fits your data, evolution plans, and caching strategy.

Need help building powerful APIs? Hire NodeJS developers with expertise in both REST and GraphQL.