REST vs GraphQL vs gRPC: Which API is Right for Your Project?

Learn the difference between REST, GraphQL and gRPC. This detailed comparison covers the pros and cons and top use cases of each API to help you choose the right one.

Are you a developer looking to build an API? If so, you’re probably familiar with the age-old question: which API should I use? There are a ton of options out there, but three of the most popular are REST, GraphQL, and gRPC.

REST, the granddaddy of APIs, has been around for a while and has become the de facto standard for many developers. It’s simple, easy to understand, and great for building scalable, stateless systems. On the other hand, GraphQL is the new kid on the block, promising a more efficient and flexible way to fetch data. And then there’s gRPC, a relatively new API that’s gaining popularity for its high performance and versatility.

So which one should you choose? Let’s compare when you should use REST vs GraphQL vs gRPC and learn their ideal use cases. By the end of this article, you’ll have a better understanding of which API is right for your project.

But before we dive into the nitty-gritty details, let’s start with the basics: what are REST, GraphQL, and gRPC, and why are they important?

Let’s find out.

What is REST?

REST, or Representational State Transfer, is an architectural style for building web services. At its core, REST is all about resources: each resource has its own unique URI, and you can interact with it using a set of standard HTTP verbs (GET, POST, PUT, DELETE, etc.).

One of the biggest strengths of REST is its simplicity. Because it’s based on standard HTTP, it’s easy to understand and use (using it is exactly like browsing the web, it can hardly get more intuitive than that!). Plus, because REST is stateless, there are a lot of problems we simply get to ignore and it’s great for building scalable systems.

However, REST isn’t without its weaknesses. One of the biggest drawbacks of REST is that it can be inefficient when dealing with large amounts of data. Because each resource has its own URI, you often need to make multiple requests to fetch all the data you need.

For example, imagine having a Bookstore system and you have to list all books that have been bought during the month of June, 2022. If you’re properly managing resources with rest, you might need to send several requests per order:

GET /orders=month=6&year=2022 #to get all the sell orders from that month
GET /books/[book_id] #for each book in the order, we get the basic details of it (like title, author id, etc)
GET /authors/[book.author_id] #for each book, we use the author_id parameter and request the details of the author (like name, age, etc)

Say you’ve sold 30 books during that month, for each book, you have to make 1 request per book for basic details, plus one request per book for the author’s details. That’s potentially 60 requests to the back-end of your system to list the sales of a single month.

Granted, you could improve the information architecture of your system to avoid that problem, but it’s a potential pitfall of REST APIs, one that you can’t really ignore.

In the end, these problems can result in a lot of unnecessary network traffic and slower response times.

That being said, REST is still the go-to choice for many developers. It’s used by some of the biggest players in the tech industry, including Google and Amazon. Plus, because it’s so ubiquitous, there are a ton of libraries and tools available for working with REST APIs.

So if you’re building a web service and need a simple, scalable way to interact with it, REST might be the way to go. But if you need something more flexible, you might want to consider GraphQL, which we’ll discuss in a second.

What is GraphQL?

GraphQL is a query language for APIs that was developed by Facebook. Unlike REST, which requires multiple requests to fetch related data, GraphQL allows you to retrieve all the data you need in a single request. This makes it much more efficient, especially when dealing with large amounts of data.

Another advantage of GraphQL is its flexibility. With REST, the server dictates what data is returned, but with GraphQL, the client specifies what data it needs. This means you can easily tailor your requests to get exactly the data you need, without any extraneous information.

However, GraphQL isn’t without its drawbacks. Because it’s relatively new, there aren’t as many tools and libraries available as there are for REST. Plus, because the client specifies what data it needs, it can be more difficult to optimize your API for performance.

Consider the same bookstore example from before. If you’re using GraphQL instead of REST, you’d send a request similar to this one:

query {
 salesByMonth(month: "June", year: 2022) {
   book {
     title
     description
     author {
       name
       age
     }
   }

 }
}

This query would retrieve all the sales data for the month of June 2022, including the book title and the author’s name and age. The salesByMonth field is a custom field that would need to be implemented on the server side, but it demonstrates the flexibility and power of GraphQL’s querying capabilities.

Despite all drawbacks, GraphQL has become increasingly popular in recent years. It’s used by a number of big companies, including GitHub and Shopify, and has a thriving community of developers contributing to its ecosystem.

So if you need a more efficient, flexible way to fetch data from your API, GraphQL might be the way to go. But if you need even more performance and versatility, you might want to consider gRPC.

So let’s dive right in!

What is gRPC?

gRPC is a high-performance RPC (Remote Procedure Call) framework developed by Google. Like REST and GraphQL, gRPC allows you to build APIs, but it differs in a few key ways.

First, gRPC uses a binary format for its messages, which makes it much more efficient than REST or GraphQL, especially for large payloads. Second, gRPC uses protocol buffers for its serialization, which is a language-agnostic way of serializing structured data. This means you can easily generate client libraries in a variety of languages.

Another advantage of gRPC is its support for bidirectional streaming. This means that both the client and server can send and receive data simultaneously, making it ideal for use cases like real-time chat or gaming. Notice how this is the first time in the article that the word “streaming” has been written. That’s because the previous two alternatives don’t have native support for it. This would be a major deciding factor if you were still on the fence regarding which one to use.

However, gRPC isn’t without its drawbacks. Because it’s optimized for performance, it can be more difficult to set up and use than REST or GraphQL. Plus, because it uses a binary format, it can be more difficult to debug when something goes wrong.

Despite these drawbacks, gRPC has become increasingly popular in recent years, especially in the microservices space. It’s used by a number of big companies, including Netflix and Uber, and has a growing ecosystem of libraries and tools.

While gRPC might be more verbose than GraphQL, it offers superior performance and scalability, especially in large-scale microservices architectures.

So if you need a high-performance, efficient way to build APIs, gRPC might be the way to go (especially so if you need something that works real-time).

How to choose between REST, GraphQL and gRPC?

We’ve covered the main highlights of each type of API by now, and we’ve also mentioned where each one shines.

So if you already have a use case in mind, you should be ready to make the call. However, if you don’t have any particular project in mind, here is a quick rundown of the type of use cases for each type of API:

When should I use REST?

REST is a great choice for situations where:

• You have a simple API with a limited number of endpoints.
• Your data is structured in a hierarchical manner (such as with a traditional SQL database).
• You need a stateless API that can be easily cached.
• You want to use HTTP’s built-in caching and authentication mechanisms.

Some common use cases for REST include:

• Retrieving information about a single resource (such as a user or product).
• Submitting data to the server (such as updating a user’s information).
• Retrieving a collection of resources (such as a list of products).

When should I use GraphQL?

GraphQL is ideal for situations where:

• You have a complex API with a large number of endpoints.
• Your data is not structured in a hierarchical manner (such as with a NoSQL database).
• You want to provide clients with the ability to request only the data they need.

Some common use cases for GraphQL include:

• Building a client-side application that needs to retrieve data from multiple sources.
• Providing a flexible API that can evolve over time without breaking existing clients (while this is also possible with REST, it’s much easier to do with GraphQL).
• Allowing clients to query for exactly the data they need, reducing the amount of data transmitted over the network. Which can be a major benefit if your app is used on slow mobile networks, or by users located in remote areas where the connection isn’t always that stable.

When should I use gRPC?

gRPC shines in situations where:

• You need a high-performance API that can handle a large number of requests.
• You need to transmit large amounts of data between the client and server.
• You want to use a strongly-typed API that can be generated automatically.
• You want to use bi-directional streaming to enable real-time communication between the client and server.

Some common use cases for gRPC include:

• Building a microservices architecture that requires fast and efficient communication between services.
• Developing real-time applications that require bi-directional communication between the client and server.
• Building APIs for resource-constrained environments where bandwidth is limited.

Of course, these are just a few examples of use cases for each API. The best choice for your project will depend on a number of factors, including the size and complexity of your API, the type of data you’re working with, and the performance and scalability requirements of your application.

It can also depend on business factors, apart from purely technical considerations. If you have a user base that is heavily invested in a particular API technology, the cognitive load on your users and your support team created by introducing a new API technology may outweigh the technical benefits, or at least tip the scales differently. The team at Camunda discovered this with the Tasklist component of Camunda Platform 8. Tasklist was initially released with a GraphQL API, based purely on a technical comparison. However, the team found in practice that users requested a familiar REST API interface to leverage their existing experience, and to match other Camunda APIs that they were consuming.  

And mind you, the list presented here is illustrative at best, since you can pretty much achieve any type of behavior using either REST, GraphQL or gRPC. Granted, it won’t be pretty and you’ll have to code your way around many problems, but mostly everything is possible. However, the use cases presented here are the ideal ones for each type and you should consider them when picking the right technology for your project.

So what’s the best API: REST, GraphQL or gRPC?

REST, GraphQL, and gRPC are all powerful tools for building APIs. REST is like an old friend — reliable and easy to work with, but sometimes a little too chatty. GraphQL is like the cool new kid in school — flexible and exciting, but can be overwhelming at times. And gRPC is like the muscle-bound athlete— powerful and efficient, but maybe a little too intense for everyday use.

Ultimately, the choice of API will depend on your specific needs and circumstances. Are you building a small, simple API? REST might be the way to go. Need to handle complex data and queries? GraphQL could be your best bet. Building a high-performance, real-time application? gRPC might be just what you need.

So go forth and choose your API wisely—just remember that whatever you choose, you’ll always have to deal with the quirks and idiosyncrasies of the API world.

But hey, that’s what makes it fun, right?

Learn more about APIs and Camunda

Curious how to use APIs to interact with Camunda Platform 8? Check out our docs to learn everything you need to know about APIs and Camunda Platform. Or find out more about how Camunda can help you with process automation and orchestration at the link below.