gRPC Transcoding: REST and gRPC in One Service

Browsers cannot call gRPC directly (no HTTP/2 trailers). gRPC Transcoding exposes your gRPC service as a REST API automatically.

import "google/api/annotations.proto";

service Greeter {
  rpc SayHello (HelloRequest) returns (HelloReply) {
    option (google.api.http) = {
      get: "/v1/hello/{name}"
    };
  }
}

Now GET /v1/hello/World calls the gRPC method. You maintain one codebase, two protocols.