gRPC vs. REST: Comparing Key API Designs And Deciding Which One is Best

Explanation of RPC

As gRPC works on similar lines as RPC to an extent, it’s wise to learn about RPC (Remote Procedure Call) first. Using a client-server design style, RPC permits a distant server to request a function. It is a well-known web architecture. 

Respondent functions are bound to follow a predefined format and the respective response will stick to the same format. The server format has no role to play in request/response processing.

Also, the client is blocked until the request is being verified. No one will be able to learn about the hidden internal messages that the server is sending/passing as a part of the request/response generation process.

If one wants to learn about the method that RPC API uses to submit a function call then checking the URL will help out the most as it’s mentioned there. RPC provides support for processing calls in a local as well as distributed ecosystem with the same perfection.  

In addition, RPC also has pre-defined rules for interactions between client-server, and the client can propose a call.

Explanation of gRPC

Google RPC is designed by skilled engineers at Google. Derived from RPC, gRPC is an open-source API architecture widely used in microservices development. 

The use of this API leads to speedy communication among microservices due to the involvement of HTTP/2.0 protocol that functions bidirectionally. Also, the use of gRPC API lets developers design applications that support various languages.

What’s worth noting here is that developers and servers won’t be able to know about HTTP while using gRPC API. It eliminates the need for finding out the process by which RPC is integrating to HTTP and simplifies the process.

Some of the key traits of gRPC are mentioned below:

• The quick and effective data serialization that leads to swift response delivery is possible as gRPC uses the Protobuf as its format for messaging.
• HTTP is used in the transport layer of any web-enabled app as it enables developers to select function calls as per the need of the hour.
• The coding complexity is reduced with gRPC as the API permits sender and receivers to accept remote calls as local ones.
• RPI is explained in IDL which makes remote call execution easier than before. 

In short, gRPC features everything possible that will make remote call execution straightforward. This is what paved the path for its unmatched popularity amongst modern-era application developers. 

Explanation of REST

REST came into being when the concept of API took birth. Aim of launching Representational State Transfer was to provide end-to-end internet and microservices interoperability. This well-known and very old API architecture has been used widely to design APIs for web apps and microservices.

REST API supports GET, POST, PUT, and DELETE action on the data used. REST API is highly supportive when it comes to message format. Almost all the leading formats work with REST API. But, the most compatible one is JSON because it’s utterly human-readable and flexible. It banks on HTTP for seamless microservices connections.

When REST API is available as web services, each service represents a resource to the client. Data is transmitted in the form of JSON objects through it in general.

REST API takes the form of RESTful API when it achieves an unvarying interface, becomes client-server independent and stateless, and delivers code on demand. Also, being cacheable and following a layered architecture are two distinct features of RESTful API. 

Have a look at a few key facts about REST API:

• Users of this API have to use server-forwarding parameters to design URLs.  
• The REST API-generated response will forward to back-end data via XML or JSON message format. 
• The client-side of a REST API ecosystem isn’t forced to understand the URL format 
• Applications built using REST API tend to follow URLs without any thinking. 
• Using REST API is easy as a wide range of REST API management tools is offered. 

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Comparing gRPC and REST

REST API started the API architecture revolution. But, its drawback is covered by gRPC. A seasoned developer is the one that pays close attention to gRPC vs REST performance and makes decisions accordingly. We’re going to help you with the task with the below-mentioned text.

Working Model

The very first comparison criteria are the working model of both these APIs. In the case of REST API, the key working model goes as defining the web API principles in advance and following it without any regulations. It lacks an in-built code creation facility and forces developers to take the help of 3rd party resources that will make API - request-based code creation possible.

On the other hand, gRPC’s working model is based on using a pre-defined .proto file. The file provides standard data exchange guidelines that involved clients and servers must abide by. While REST fails to create in-built codes, gRPC offers it by default. gRPC can support tons of languages and is open for 3rd party integration. 

As code generation is supported, it’s easy for developers to design SDKs.  

Verdict - When RESTful vs gRPC is analyzed on the working model basis, we would suggest using REST API when you want to have a flexible working model. gRPC is great when you need an in-built code creation facility.

Browser Support

As API uses the internet and browser to complete the communications, it’s important to understand the browser support both these APIs proffer.

REST APIs are based on HTTP/1.1 and are open for all sorts of browsers. You can use it on any browser without meeting harsh prerequisites. gRPC is based on the HTTP/2.1 protocol. 

This protocol isn’t as famous or popular as HTTP/1.1. Also, not many browsers are compatible with this protocol. Hence, you don’t have much of a choice when it comes to compatible browsers for gRPC. 

Only a handful of browsers are useful when you’re using gRPC API.  

Verdict - With REST, you don’t have to be concerned about the kind of browser your application would be using as it works on all kinds of browsers. But, be ready to face high latency. gRPC may have limited browser support but latency isn’t an issue. So, choose based on your preference.

HTTP 1.1 vs HTTP 2

Both the APIs use different versions of the HTTP protocol. So, let’s try to understand how these two versions are different from each other so that we have better clarity over REST vs gRPC for microservices.

HTTP/1.1 is the very first update that customary HTTP received. This version is capable of handling only one request at a time and demands new requests for different responses. This makes it a bit slow.

Seeing this drawback, certain changes were made to the REST API so that it can use HTTP/2. Gladly, the efforts brought successful results. But, the presence of the request-response model restricted penetration of HTTP/2 as well. REST API isn’t capable of using the bidirectional support and streaming communication features of HTTP/2.  

gRPC is built on HTTP/2 by default. Hence, no restrictions in using HTTP/2 are imposed. 

This protocol is based on a client – a more flexible response model. This model allows the client to receive multiple responses against one request. There is no need to generate new requests for new responses. 

As long as the connection is active, the client will keep on receiving the responses. Because of this ability, this protocol is famous for streaming communication. In addition, HTTP/2 on gRPC is responsible to support unary and client streaming as well.

Verdict - HTTP/1.1 is more flexible and is supported by most browsers. But, it fails to provide continual data delivery in real-time. HTTP/2 is limited but is highly useful for real-time and continual data delivery.

Latency

REST API experiences high latency. It’s because of the use of TCP handshake. This handshake requires a separate handshake for every new request. It consumes more time and resources.

As far as latency is concerned, gRPC renders low latency as it permits multiple requests over a single TCP connection. As long as a connection is active, the server keeps on pushing requests to the client. 

Verdict - Here, the clear winner of gRPC vs REST API is gRPC as latency is low which leads to quick data delivery.

Data Exchange Format

Both these APIs are here to make sure that the data between client and server is exchanged without any hassles. That’s the basics of internet communication. Now, the point is which one does it easily?

REST supports multiple data exchange formats. But, the most commonly used ones are XML and JSON.  

When JSON is used, developers are allowed to transfer data dynamically. JSON doesn’t put the rigid structure of data into consideration. As JSON is easy for humans to understand, and therefore, ideal for non-critical data’s transmission.

gRPC is only compatible with Protocol Buffers for reliable data transfer. As a developer, you won’t have many choices. Protocol Buffers can compress the data and make transmission faster than what you would experience with REST API. If you’re skilled, you can make REST API compatible with Protocol Buffers. But, it would be very insignificant. 

Verdict - REST is here to make data transfer possible in multiple ways. JSON is easy to work with. But, speed will remain an issue. gRPC isn’t very option-offering on the data exchange front. But, whatever it offers, Protocol Buffer, it’s the best in class as it’s the fastest option offered. 

Serialization

gRPC adopts an agnostic serialization format and uses Protocol Buffer to achieve the same. On the contrary, in REST, serialization is attained by converting intricate data into easy-to-understand native Python data that is understandable by XML and JSON.

Code Generation Features

As mentioned above, REST API doesn’t have any default code generation ability. Despite that, REST asks for more codes. Each request will consume more codes and request processing makes code-handling complex. Straightforward coding isn’t a REST API’s thing.

Developers have to rely on 3rd party tools that can generate codes for a REST API request. While there is no dearth of dependable options, using an outside tool and ensuring its effective integration is a tough task to pull off. Also, it demands continual monitoring of the code’s quality.  

On the contrary, gRPC offers a pre-tailored code generation facility. All thanks go to the Protoc compiler. The compiler makes this API type flexible enough to work with various kinds of languages and this is what makes gRPC useful for microservices development. 

The in-build code generator empowers developers to design SDKs as per the product requirements. Writing codes is a piece of cake with gRPC as this API provides clients with native objects. Furthermore, gRPC is capable of fixing pre-existing errors.

Verdict - Indeed, code generation is swift with gRPC. 

When to use REST?

Owing to the properties and features REST has, its usage will bring maximum benefits when the development goal is to develop a secured internal system. Also, it holds equal significance in the development of a system that has controlled exposure to the outside world.

Use it when you expect your application to feature swift iteration along with HTTP connection standardization. If you want to offer ample integrations via your application, try REST as it comes with in-build support for thousands of 3rd party tools. This way, incorporating integration won’t be an issue.

Using REST is a wise choice to make when you’re developing cloud-based applications. It’s possible because of the Stateless Calls that REST API can easily make. These calls ensure that the load changes are easily incorporated into the cloud application in case of any technical fault.

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When to use gRPC?

gRPC has to come a long way to achieve the community and technology support that REST API has earned. Present-era 3rd party tools are still not equipped enough to provide out-and-out support to gRPC. Hence, its usage area is limited. Mostly, it’s preferred for the development of internal systems. Also, it’s a wise choice to make when you need to build an application that isn’t available to outsiders.

It’s preferred when developers need to establish a lightweight microservices connection; it offers reduced latency and quick data delivery. 

Microservices that demand real-time message delivery can make it happen with the help of gRPC. The use of HTTP/2.0 promotes message/data delivery.

We have already mentioned that gRPC can make one application to support multiple languages. So, use this API when you need to develop a multilingual application. This capability comes from gRPC’s support for native code systems. Also, gRPC allows developers to easily manage the polyglot ecosystem’s connection.

Applications that need to fetch real-time data must be developed via gRPC as it supports two-way streaming. If developers have access to the network that features low power and bandwidth then using gRPC is a smart move as gRPC uses Protocol Buffer message format. It’s a highly serialized message format that supports lightweight messaging. 

Even with reduced development resources, gRPC will make development possible. You can use it for mobile apps because the API doesn’t ask for any browser.

Final Conclusion

API and its effective usage warrants flawless application development. But, choosing the right API matters the most. REST and gRPC are two very famous rivals in the world of APIs. Each one comes with a distinct set of advantages, features, and drawbacks. One must first figure out the purpose of development and then align it with the requirements of the API offering.

For instance, REST API is a great choice to make when static data is in use while gRPC deals with updated and moving data. The above-detailed comparison of gRPC v/s RESTful API will help you make an astute decision. 

Before we finally wrap up, let us tell you one more crucial thing that is taking the help of an API security platform. Regardless of the API picked, ensuring its security is important to reduce misuse of APIs and compromising the data they are carrying. Without API security, API usage isn’t promoted.