JSON-RPC vs gRPC: What are the differences?

Both JSON-RPC and gRPC are remote procedure call (RPC) protocols, but they differ in various aspects. Let's explore the key differences between JSON-RPC and gRPC.

1. Serialization Format: JSON-RPC uses JSON (JavaScript Object Notation) as its serialization format, which is a human-readable data interchange format. On the other hand, gRPC uses Protocol Buffers (protobuf) as its default serialization format, which is a binary format that provides a compact representation of structured data.

2. Transport Protocol: JSON-RPC typically relies on HTTP/HTTPS as its transport protocol, making it suitable for web-based applications. Meanwhile, gRPC offers flexibility by supporting multiple transport protocols, including HTTP/2, which provides features like multiplexing and server push, making it more efficient for high-performance and real-time communication.

3. Language Support: JSON-RPC has broader language support as it can be implemented in any programming language with JSON and HTTP/HTTPS capabilities. Conversely, gRPC is designed to work with Protocol Buffers, which requires code generation to create client and server stubs, making it more suited for specific languages with official support like C++, Java, Go, and more.

4. Service Definition: JSON-RPC does not have a standardized way to define the available methods and their input/output parameters. Hence, developers need to manually document and agree upon the API structure. In contrast, gRPC uses Protocol Buffers to define services and messages in a language-agnostic manner. This approach allows for automatic code generation, making it easier to maintain and update APIs.

5. Interoperability: JSON-RPC is generally more interoperable as it relies on common technologies like JSON and HTTP/HTTPS, which are widely supported across different platforms and frameworks. On the other hand, gRPC, by default, uses Protocol Buffers as its serialization format, which may require additional work to integrate with systems that do not natively support it.

6. Streaming Support: gRPC provides built-in support for bidirectional streaming and server-side streaming, allowing clients and servers to send multiple requests or responses over a single TCP connection. JSON-RPC, on the other hand, lacks native support for streaming and typically relies on multiple requests/responses to achieve a similar effect, which may introduce additional latency and overhead.

In summary, JSON-RPC offers broader language support and better interoperability, gRPC provides superior performance, flexibility, and streaming capabilities at the cost of narrower language support and additional complexity in service definition.