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Manuel Aparicio
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gRPC vs REST for System Communications


Web Services Development demands robust tools and protocols for system communication within Microservices Architectures. As a result, choosing the best Application Programming Interface (API) architecture to manage distributed systems communication is a major decision for developers! 

REST (Representational State Transfer) and gRPC (Google Remote Procedure Call) have gained significant traction in recent years. But of course, understanding both REST and gRPC is key when choosing the best stack for your project. This article will focus on the basics and differences between gRPC vs REST. Let’s go! 

What is REST?

REST, short for Representational State Transfer, provides a standardized way to manage client-server communications. Since you can use REST with a wide variety of programming languages, it’s highly adaptable and widely used across different platforms. A great example is RESTful API architectures, which allow for scalable and interoperable web services without the need for strict structures, thanks to JSON.

A key principle of REST is that its resources are identified with unique Uniform Resource Identifiers (URIs), which can represent entities like users, products, or orders and are manipulated using HTTP methods. Further, REST is a widely adopted architectural style for designing networked applications since it emphasizes a stateless, client-server communication model. 

Each REST request from client to server must contain all the needed info, yet the cooler part is that it doesn't rely on previous communication or state. RESTful APIs use HTTP methods such as GET, POST, PUT, and DELETE to perform operations on resources, which allow clients to retrieve, create, update, and delete resources. That makes REST a versatile and flexible choice for building web services.

What is REST Architecture?

The emphasis in REST architecture is on the resources the API exposes. A unique URL identifies a resource or collection of resources, and clients interact with them using HTTP methods. REST promotes loose coupling between client and server, easing scaling and system evolution over time. It further leverages JSON text-based formats as its default message format, making it quite very popular with JavaScript and related tools like React.js and Node.js.

One of the key principles of REST is the use of hypermedia, which means that the API responses contain links to related resources. As a result, clients can navigate it and discover new resources without having prior knowledge of the structure. Another strength is its compatibility with existing web infrastructure. Since REST API requests use standard HTTP methods and status codes, they can easily leverage existing caching mechanisms, load balancers, and other web techs.

What is gRPC?

gRPC is a modern high-performance RPC (Remote Procedure Call) framework. Developed by Google, gRPC focuses on efficient and fast communication between clients and servers. Yet, while it can handle client-server calls, it was specially built for communication between Microservices- or individual Back-End systems. 

Instead of HTTP as the underlying protocol, gRPC uses Protocol Buffers, a language-agnostic interface definition language, to define services and message types. Also known as protobuf or proto files (".proto'), Protocol Buffers provide a way to define the data structure exchanged between systems, allowing for efficient binary serialization, smaller payload sizes, and faster transmission. gRPC generates the necessary client code and servers to allow seamless communications without external tools.

A key advantage of gRPC is its support for languages like C++, Java, Python, and Go. Since developers can use their preferred language to define services and interact with them, this feature makes gRPC a versatile choice for polyglot environments. Moreover, gRPC supports unary server streaming, client streaming, and bidirectional streaming, providing more flexibility in complex systems that need real-time communication or data streaming.

What is gRPC Architecture?

gRPC follows a contract-first approach, where devs define their services and message types with Protocol Buffers, and gRPC generates the client and server code. This approach separates concerns between API definition and implementation, making it easier to maintain and evolve. Here, teams define the behavior of gRPC APIs with procedures, working as individual methods within services. You can think of gRPC procedures as addressable entities that represent actions clients can call on a server.

gRPC uses HTTP/2 as the underlying HTTP protocol, bringing several advantages over traditional REST. A key feature of HTTP/2 is multiplexing, which allows multiple requests and responses to be sent over a single connection simultaneously. This feature reduces latency and improves overall performance, especially in scenarios with high network latency, which is particularly useful in real-time streaming apps where both parties need to exchange data continuously.

A huge strength of gRPC is its support for different serialization formats. Yes, Protocol Buffers is the default choice, and its binary serialization format makes data exchange highly efficient. Yet, gRPC also supports JSON and other data exchange formats, allowing developers to choose the most suitable option. What’s more, gRPC provides built-in support for authentication, load balancing, and error handling, which is key to simplifying processes and handling critical aspects across services.

Comparing REST vs gRPC

Performance is a crucial factor when choosing an architectural style for your application, so let's compare the performance of REST and gRPC based on some key factors.

REST vs gRPC in Language Support

In the case of REST, you can handle REST API implementations with any programming language that supports HTTP. This flexibility is one of the main reasons it’s popular for applications developed in various programming languages.

Contrariwise, gRPC develops client and server code in the previously chosen language, making it easier to integrate it into existing projects regardless of the used languages.

REST vs gRPC in Security 

When using REST, devs can choose security measures, including HTTPS, OAuth, JSON Web Tokens (JWT), and API keys. However, the development team implements and manages these security measures.

In contrast, gRPC provides built-in transport security with Transport Layer Security (TLS), formerly known as SSL. TLS encrypts the communication between the client and server and ensures messages are securely transmitted and protected. Moreover, gRPC requires both the server and client to have special software for the protocol implementation.

REST vs gRPC in Speed and Efficiency

One of the reasons gRPC performance surpasses REST in speed and efficiency is its use of binary serialization. Unlike REST, which typically uses JSON or XML Format, gRPC uses a binary format that leads to smaller message sizes, reducing the needed data to be transmitted over the network.

gRPC also takes advantage of HTTP/2, which introduces multiplexing and header compression to improve performance. While multiplexing reduces latency and improves overall throughput, header compression reduces the size of the headers sent with each request, further lowering network overhead.

By combining binary serialization, HTTP/2, and multiplexing, gRPC achieves faster and more efficient bidirectional communication compared to HTTP/1.1. However, HTTP/2 doesn't have universal browser support yet, and browser compatibility is still a huge factor in systems development. That's why gRPC is mainly used for internal services or transmission data transmission between microservices.

REST vs gRPC in Data Transfer Rates

Since HTTP/2 is designed to handle concurrent requests more efficiently than its predecessor, HTTP/1.1., gRPC seems to beat REST once again. HTTP/2 handles multiple requests and responses concurrently over a single connection and introduces a prioritization mechanism in addition to concurrent requests. 

This way, HTTP/2 ensures quick delivery even in the presence of other ongoing requests, which is particularly beneficial when dealing with large payloads. Overall, gRPC's use of HTTP/2 gives it a significant advantage in terms of data transfer rates, especially when dealing with large payloads or a high volume of concurrent requests.


The choice between REST and gRPC depends on the specific requirements and the trade-offs you are willing to make. Both support JSON, which makes them excellent options for Software Development despite their notable differences. gRPC has features to build modern and larger applications, including mobile development. While gRPC is more modern and language-neutral, REST is still the most common choice. 

By considering performance, support, and security, you can make an informed decision that aligns with your goals and needs. Ready for your next project? Happy developing!