gRPC

gRPC is a high-performance RPC framework developed by Google. It uses HTTP/2 for transport and Protocol Buffers (Protobuf) for compact, binary data serialisation.

Key Features

• RPC model → Call methods like local functions (GetUser(id)).
• HTTP/2-based → Supports multiplexing, compression, streaming.
• Strongly typed contracts → Defined with Protobuf .proto files.
• Supports bi-directional streaming.

Advantages

• Very fast & efficient (binary messages).
• Cross-language support (many SDKs).
• Excellent for microservices.
• Streaming support → Real-time communication.

Disadvantages

• Requires tooling (Protobuf compilation).
• Less human-readable than JSON.
• Not always best for public APIs (steeper adoption curve).
• Browser support limited (needs gRPC-Web for JS apps).

Common Use Cases

• Microservices communication.
• High-performance backend systems.
• Real-time apps (chat, video, IoT).
• Internal APIs where speed matters.

Security

gRPC also doesn’t have built-in auth — it uses transport-level or metadata-based auth:

• TLS / mTLS → Mutual authentication using certificates.
• JWT or OAuth 2.0 tokens → Sent as metadata in each RPC call.

Example request

Before making requests, you define a service in a .proto file:

syntax = "proto3";​package user;​service UserService {  // Get user by ID  rpc GetUser (GetUserRequest) returns (GetUserResponse);}​// Request messagemessage GetUserRequest {  int32 id = 1;}​// Response messagemessage GetUserResponse {  int32 id = 1;  string name = 2;  string email = 3;}

Explanation:

• rpc GetUser defines a remote procedure.
• GetUserRequest and GetUserResponse define the request and response messages.
• The client calls GetUser like a local function.
• gRPC handles serialisation, transport, and deserialisation automatically.
• The server will return a binary Protobuf message, which the client automatically decodes.
• Internally, this is transmitted in compact binary format over HTTP/2, not plain text.
• You don’t see raw JSON unless you use gRPC-Web or a debugging tool.