Comparing REST API and gRPC - Choosing the Right Web API

Apr 10, 2020 · 3 min read · system design software engineering ·

REST (Representational State Transfer) and gRPC are two different techniques for creating web APIs (Application Programming Interfaces).

What is REST API?

A popular architectural design for developing web APIs is REST. It is built on the HTTP (HyperText Transfer Protocol) and operates on resources defined by URLs using common HTTP methods including GET, POST, PUT, and DELETE. REST APIs are simple to use with a variety of programming languages and tools since they exchange data using the JSON (JavaScript Object Notation) format.

REST is a robust approach to web APIs that enables the development of intricate systems with numerous associated resources. A REST API's URL structure frequently illustrates the connections between various resources, making it simple to understand the API and interact with its data.

What is gRPC?

A high-performance, open-source framework for creating web APIs is called gRPC. It is more efficient and compact than JSON since it exchanges data using the Protocol Buffers binary format. The fact that gRPC offers bi-directional streaming, which enables clients and servers to send and receive data in real-time while maintaining low latency, makes it the perfect choice for applications that manage massive amounts of data.

A service is described as a group of methods that may be called over the network, and the foundation of gRPC is the concept of services. Protobuf files, which are used to create client and server stubs automatically, include descriptions of these methods. This produces a strongly-typed API where the message's structure and data types are predefined, improving type verification and error handling.

Differences between REST API and gRPC

Data format: REST APIs use JSON, while gRPC uses Protocol Buffers. Protocol Buffers are smaller and faster than JSON, but are less human-readable and require a code generation step.

API design: REST APIs are based on resource-oriented URLs and HTTP methods, while gRPC is based on defining services and methods in a Protobuf file. This leads to a more strongly-typed API in gRPC, but can make the API more difficult to evolve.

Performance: gRPC is generally faster and more efficient than REST because it uses binary data and a compact message format, and supports bi-directional streaming. REST is typically slower and less efficient because it uses text-based data and requires larger message sizes.

Language support: gRPC has official client libraries for many programming languages, and is easier to use with languages that have native support for Protocol Buffers, such as C++, Java, and Go. REST is more language-agnostic, but requires more manual work to handle serialization and deserialization of data.

Error handling: gRPC has built-in error handling, with the ability to return detailed error information in response to a failed request. REST typically relies on HTTP status codes to indicate success or failure, and additional error information must be included in the response body.

When to use REST API?

When you require a flexible, language-independent API that is simple to use.
When you want to exchange data via a standardized, known protocol.
Sometimes, you must integrate JSON-using systems.
When you wish to develop a simple, easy-to-use API without needing bi-directional streaming or real-time communication.
When you want to make it possible for your API to easily modify over time without requiring significant changes to the underlying code.

When to use gRPC?

When you need high performance and efficiency, especially for programs that handle with lots of data or demand fast response times.
Sometimes a strongly-typed API with integrated error handling is what you wish to use.
When you are utilizing a language, such as C++, Java, or Go, that comes with native support for Protocol Buffers.
When you need to provide real-time data transmission and reception between clients and servers via bi-directional streaming.
To strengthen type checking and error handling and to impose a consistent structure and data types for your API.