Unary

Greeter Service

The simplest pattern. The client sends one request and gets exactly one response back, like a normal function call.

1 request → 1 response

1. The contract

This is real gRPC code. It defines the service and messages.
greeter.proto
syntax = "proto3";

package demo;

// UNARY: one request in, one reply out
service Greeter {
  rpc SayHello (HelloRequest) returns (HelloReply);
}

message HelloRequest {
  string name = 1;
}

message HelloReply {
  string message = 1;
}

2. Live simulation

Watch how messages flow for this pattern.

// Press the button to start the Unary demo.