When to Use REST APIs or gRPC?

APIs are required for coupling different software programs. You develop a web app, an in-phone application or a big distributed system – choosing an API technology makes the difference. The two most commonly used patterns for API communications are REST APIs and gRPC. But where does one use REST and when would one use gRPC? This blog will explain both, contrast their weakness and strength and help you decide which one to use on your next project.

What is REST API?

REST (Representational State Transfer) is a widely used that follows certain rules for communication over the internet. It is based on standard HTTP methods like:

GET – to retrieve data
POST – to send new data
PUT – to update existing data
DELETE – to remove data

REST APIs use JSON (JavaScript Object Notation) or sometimes XML to send and receive data. Since REST is stateless, each API request from a client contains all the information needed to process it.

Advantages of REST APIs

1. Widely Used and Supported
   • Almost all programming languages and platforms support REST.
   • It works well with web browsers, mobile applications and microservices.
2. Human-Readable Data (JSON)
   • JSON is easy to read and understand.
   • It can be used in frontend and backend development.
3. Simple and Easy to Use
   • REST follows HTTP standards, making it simple to implement.
   • Debugging REST APIs is easier due to the human-readable format.
4. Works Well Over the Internet
   • REST uses HTTP which is ideal for web applications and public APIs.
   • It does not require special network settings.

Disadvantages of REST APIs

1. Slower Performance for Large Data
   • REST messages are in JSON, which is not as fast as binary formats.
   • This makes REST less efficient for high-speed communication.
2. No Built-in Streaming
   • REST APIs do not support real-time streaming.
   • If a server needs to push updates to clients in real time, REST is not the best choice.
3. More Data Overhead
   • JSON and HTTP headers add extra data to requests and responses.
   • This can slow down performance in high-volume systems.

What is gRPC?

gRPC (Google Remote Procedure Call) is a modern API technology developed by Google. It is designed for high-performance communication between applications. gRPC uses Protocol Buffers (Protobuf), a compact and efficient data format instead of JSON. Unlike REST, gRPC allows direct function calls between different systems. It also supports advanced features like real-time streaming.

Advantages of gRPC

1. Fast and Efficient
   • gRPC uses Protobuf which is smaller and faster than JSON.
   • It reduces the size of API requests, improving speed and efficiency.
2. Supports Streaming
   • gRPC allows real-time communication between client and server.
   • This is useful for chat applications, live updates and streaming services.
3. Strong Type Checking
   • Protobuf ensures data consistency with strict type definitions.
   • This helps avoid data errors.
4. Multiplexing and Efficient Connections
   • gRPC uses HTTP/2 which allows multiple API calls over a single connection.
   • This reduces network latency and improves performance.

Disadvantages of gRPC

1. Complex Setup
   • gRPC requires learning Protocol Buffers and setting up special tools.
   • Debugging gRPC can be more difficult compared to REST.
2. Not Supported by All Browsers
   • REST APIs work directly in browsers but gRPC does not.
   • If your application requires web browsers to call APIs, REST may be a better choice.
3. Harder to Read Data
   • Unlike REST’s JSON format, gRPC’s Protobuf is not human-readable.
   • This makes debugging and testing more challenging.

When to Use REST APIs?

Now that we understand REST APIs let’s see when you should use them:

1. When Your Application Needs to Work with Web Browsers
   • REST is best for frontend applications, websites and mobile apps.
   • If you need an API that browsers can call easily.
2. When You Need Simplicity
   • REST is easier to understand and use.
   • If your team is familiar with REST it can speed up development.
3. For Public APIs and Third-Party Integrations
   • Many external services and clients expect REST APIs.
   • If you are building an API for third-party developers, REST is usually preferred.
4. When Human-Readable Data is Important
   • JSON is easier to debug and inspect.
   • If you need to quickly check API responses, REST is better.
5. For Small and Medium-Sized Applications
   • If you don’t have very high-speed data requirements, REST is good.
   • It is enough for most small and mid-level applications.

When to Use gRPC?

Here are the situations where gRPC is a better choice:

1. For High-Performance Applications
   • gRPC is faster and uses less bandwidth.
   • It is ideal for systems that need fast data exchange.
2. When Real-Time Communication is Needed
   • If your application requires live streaming, notifications or bidirectional data flow, gRPC is better than REST.
3. For Microservices Communication
   • gRPC is commonly used in microservices architectures.
   • It allows different services to communicate efficiently.
4. When You Need Strong Type Safety
   • Protobuf ensures that data structures are well-defined.
   • This helps avoid errors and improves data consistency.
5. For Internal APIs in Large Organizations
   • If you are building APIs for internal use in a company, gRPC can be better.
   • It provides better performance and efficiency for backend systems.

REST vs. gRPC: Comparison Table

Both REST APIs and gRPC have their own strengths and weaknesses. If you need a simple and widely supported API for web and mobile applications – REST is the best choice. If you need high performance, real-time streaming and efficient microservices communication then gRPC is the better option.

Selecting between REST and gRPC depends on your project’s requirements. If your API will be used in web browsers and by third-party developers, REST is usually the way to go. If your system requires speed, efficiency and internal communication between services, gRPC is a great choice.

Understanding the differences between REST and gRPC will help you make the best decision for your application. Always consider performance, ease of use and compatibility before choosing the right API style.