gRPC vs REST: Which is Better for Your APIs?

QA Learning

Shreya Srivastava

Nov 24, 2023

Introduction

In the world of API development, two major players are REST (Representational State Transfer) and gRPC (gRPC Remote Procedure Call). Choosing the right one for your project can significantly impact performance, scalability, and ease of development. This blog will delve into the differences, benefits, and use cases of REST and gRPC, helping you make an informed decision.

APIs

What is an API?

An Application Programming Interface (API) is a set of rules that allows different software entities to communicate with each other. APIs enable the integration of new features and services into applications, ensuring seamless interaction between different systems.

Why APIs are Important

APIs are the backbone of modern software development. They allow developers to use existing services and frameworks, promote modularity, and facilitate rapid development. Whether it's a web application, mobile app, or cloud service, APIs play a crucial role.

What is an API?

Why APIs are Important

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Introduction to REST

What is REST?

REST, or Representational State Transfer, is an architectural style for designing networked applications. RESTful services use HTTP requests to perform CRUD (Create, Read, Update, Delete) operations.
"In simpler terms, a REST API is a set of rules that helps apps share information easily."

Key Principles of REST

Statelessness: Each request from a client to a server must contain all the information needed to understand and process the request.
Client-Server Architecture: The client and server are separate entities, promoting scalability and flexibility.
Cacheability: Responses should be defined as cacheable or non-cacheable to improve performance.
Layered System: A client cannot tell if it is connected directly to the end server or an intermediary.
Uniform Interface: Simplifies and decouples the architecture, enabling each part to evolve independently.

RESTful Web Services

RESTful web services typically use HTTP methods such as GET, POST, PUT, and DELETE. They leverage URLs to identify resources and often use JSON or XML for data interchange.

What is REST?

Key Principles of REST

Statelessness: Each request from a client to a server must contain all the information needed to understand and process the request.
Client-Server Architecture: The client and server are separate entities, promoting scalability and flexibility.
Cacheability: Responses should be defined as cacheable or non-cacheable to improve performance.
Layered System: A client cannot tell if it is connected directly to the end server or an intermediary.
Uniform Interface: Simplifies and decouples the architecture, enabling each part to evolve independently.

RESTful Web Services

RESTful web services typically use HTTP methods such as GET, POST, PUT, and DELETE. They leverage URLs to identify resources and often use JSON or XML for data interchange.

Introduction to gRPC

What is gRPC?

gRPC is a high-performance, open-source framework developed by Google. It uses HTTP/2 for transport, Protocol Buffers (protobufs) for serialization, and it supports multiple programming languages.
"In simple terms, gRPC is like a speedy messenger that helps different programs understand each other, making it easier for them to work together, even if they're far away."

Key Principles of gRPC

Efficient Communication: gRPC uses HTTP/2, which allows for multiplexing multiple requests over a single connection, reducing latency.
Strongly Typed Contracts: gRPC uses Protocol Buffers, which provide a clear and efficient way to define service methods and message structures.
Bi-Directional Streaming: Supports bi-directional streaming, enabling real-time communication.
Language Agnostic: Provides tools to generate client and server code in multiple languages.

gRPC Services

gRPC services define methods using Protocol Buffers. Each service consists of a set of RPC (Remote Procedure Call) methods that can be called remotely by clients.

What is gRPC?

Key Principles of gRPC

Efficient Communication: gRPC uses HTTP/2, which allows for multiplexing multiple requests over a single connection, reducing latency.
Strongly Typed Contracts: gRPC uses Protocol Buffers, which provide a clear and efficient way to define service methods and message structures.
Bi-Directional Streaming: Supports bi-directional streaming, enabling real-time communication.
Language Agnostic: Provides tools to generate client and server code in multiple languages.

gRPC Services

gRPC services define methods using Protocol Buffers. Each service consists of a set of RPC (Remote Procedure Call) methods that can be called remotely by clients.

REST vs gRPC: A Comparative Analysis

Performance:
gRPC generally offers better performance than REST due to its use of HTTP/2, binary serialization, and efficient communication mechanisms. REST, while still performant, can be slower due to its reliance on text-based protocols and HTTP/1.1.
Scalability:
Both REST and gRPC can scale effectively, but gRPC's efficient communication and support for bi-directional streaming can make it more suitable for high-throughput, low-latency applications.
Ease of Development:
REST is easier to implement and understand, making it a popular choice for many developers. gRPC, while more complex, offers tools and libraries that simplify development, particularly for large-scale applications.
Security:
Both REST and gRPC support common security mechanisms such as TLS. REST, with its maturity, has a wide range of security practices and tools. gRPC, being newer, also provides robust security but might require additional considerations for complex security requirements.
Interoperability:
REST, with its use of HTTP and standard data formats like JSON and XML, is highly interoperable. gRPC, while language-agnostic, relies on Protocol Buffers, which may require additional tooling for integration with systems that do not natively support protobufs.
Payload Size:
gRPC messages are typically smaller due to binary serialization with Protocol Buffers, which can lead to reduced bandwidth usage and faster transmission. REST messages, using JSON or XML, can be larger and less efficient.
Error Handling:
REST uses standard HTTP status codes for error handling, which are widely understood. gRPC has its own status codes and provides detailed error messages, offering more granular error handling.

Performance:
gRPC generally offers better performance than REST due to its use of HTTP/2, binary serialization, and efficient communication mechanisms. REST, while still performant, can be slower due to its reliance on text-based protocols and HTTP/1.1.
Scalability:
Both REST and gRPC can scale effectively, but gRPC's efficient communication and support for bi-directional streaming can make it more suitable for high-throughput, low-latency applications.
Ease of Development:
REST is easier to implement and understand, making it a popular choice for many developers. gRPC, while more complex, offers tools and libraries that simplify development, particularly for large-scale applications.
Security:
Both REST and gRPC support common security mechanisms such as TLS. REST, with its maturity, has a wide range of security practices and tools. gRPC, being newer, also provides robust security but might require additional considerations for complex security requirements.
Interoperability:
REST, with its use of HTTP and standard data formats like JSON and XML, is highly interoperable. gRPC, while language-agnostic, relies on Protocol Buffers, which may require additional tooling for integration with systems that do not natively support protobufs.
Payload Size:
gRPC messages are typically smaller due to binary serialization with Protocol Buffers, which can lead to reduced bandwidth usage and faster transmission. REST messages, using JSON or XML, can be larger and less efficient.
Error Handling:
REST uses standard HTTP status codes for error handling, which are widely understood. gRPC has its own status codes and provides detailed error messages, offering more granular error handling.

When to use REST vs. gRPC?

REST and gRPCs features make them suited for different use cases.

Best for Public Web Services: REST
REST’s features are well-suited to public web service APIs. REST uses the HTTP 1.1 protocol which has universal browser support. gRPC, on the other hand, is less compatible since it uses HTTP 2.0. While gRPC’s payload is smaller, REST’s primary payload format, JSON, is more flexible and friendly to browsers. REST also allows you to use other message formats HTML, plain text, XML, and YAML which adds to its flexibility.

Best for Internal APIs, IoT, and mobile: gRPC
gRPC has features that make it suited for internal APIs, IoT, and mobile development. These applications benefit from gRPC’s bi-directional streaming, small payload sizes, and built-in code generation. gRPC’s small message size makes it more performant and scalable than REST for these applications.
gRPC’s low browser support makes it suited to internal APIs (non-public) and mobile development. Mobile applications usually do not require a browser, and gRPC’s small message size can preserve the processing speed of the mobile device.
IoT APIs need bi-directional streaming because many devices may send messages to an API server concurrently. gRPC can process and respond to multiple requests from multiple clients at the same time. REST, on the other hand, only supports unary communication. IoT APIs also require lightweight messaging because of constrained bandwidth. Finally, it is easier to use gRPC to connect Internet of Things (IoT) devices such as phones to backend APIs.

Best for microservices: The jury is out
REST and gRPC are both used for microservices. While REST is more widely used for microservices, gRPC’s features are particularly suited to this domain.
Microservice architectures can leverage gRPC’s built-in code generation to allow microservices written in different programming languages to communicate. gRPC’s payload size and bi-directional streaming also allow faster and more efficient communication between microservices.

REST and gRPCs features make them suited for different use cases.

Best for Public Web Services: REST
REST’s features are well-suited to public web service APIs. REST uses the HTTP 1.1 protocol which has universal browser support. gRPC, on the other hand, is less compatible since it uses HTTP 2.0. While gRPC’s payload is smaller, REST’s primary payload format, JSON, is more flexible and friendly to browsers. REST also allows you to use other message formats HTML, plain text, XML, and YAML which adds to its flexibility.

Best for Internal APIs, IoT, and mobile: gRPC
gRPC has features that make it suited for internal APIs, IoT, and mobile development. These applications benefit from gRPC’s bi-directional streaming, small payload sizes, and built-in code generation. gRPC’s small message size makes it more performant and scalable than REST for these applications.
gRPC’s low browser support makes it suited to internal APIs (non-public) and mobile development. Mobile applications usually do not require a browser, and gRPC’s small message size can preserve the processing speed of the mobile device.
IoT APIs need bi-directional streaming because many devices may send messages to an API server concurrently. gRPC can process and respond to multiple requests from multiple clients at the same time. REST, on the other hand, only supports unary communication. IoT APIs also require lightweight messaging because of constrained bandwidth. Finally, it is easier to use gRPC to connect Internet of Things (IoT) devices such as phones to backend APIs.

Best for microservices: The jury is out
REST and gRPC are both used for microservices. While REST is more widely used for microservices, gRPC’s features are particularly suited to this domain.
Microservice architectures can leverage gRPC’s built-in code generation to allow microservices written in different programming languages to communicate. gRPC’s payload size and bi-directional streaming also allow faster and more efficient communication between microservices.

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Is gRPC better than REST API?

Both gRPC and REST API have their use cases. gRPC excels in high-performance environments, supports bidirectional streaming, and uses Protocol Buffers for efficient serialization. REST API is simpler, more flexible, and better suited for use with web applications or when interacting with multiple programming languages.

Conclusion

Final Thoughts
Both REST and gRPC have their strengths and weaknesses. The choice between them depends on your specific needs, such as performance requirements, ease of development, and scalability.

Which One Should You Choose?
For public APIs and simple CRUD operations, REST is often the best choice due to its simplicity and wide adoption. For high-performance, low-latency systems, and real-time communication, gRPC is a more suitable option.

Final Thoughts
Both REST and gRPC have their strengths and weaknesses. The choice between them depends on your specific needs, such as performance requirements, ease of development, and scalability.

Which One Should You Choose?
For public APIs and simple CRUD operations, REST is often the best choice due to its simplicity and wide adoption. For high-performance, low-latency systems, and real-time communication, gRPC is a more suitable option.