gRPC-Web Demo

A SayHello unary RPC sent from the browser over HTTP/1.1 via Gcore CDN — no Envoy required. The browser encodes the request as a binary Protobuf frame, nginx proxies it to a Node.js gRPC-Web server, which forwards it to a native gRPC backend over HTTP/2.

Architecture:

Browser (fetch + gRPC-Web framing) → Gcore CDN (TLS termination, HTTP/2) → nginx /grpc/ proxy_pass (HTTP/1.1) → Node.js gRPC-Web proxy :9002 (HTTP/1.1 → gRPC) → Node.js gRPC server :50051 (HTTP/2)

Tech stack:

Service definition (echo.proto)

The contract between client and server, language-agnostic:

syntax = "proto3";

service Echo {
  rpc SayHello (HelloRequest) returns (HelloReply);
}

message HelloRequest { string message = 1; }
message HelloReply   { string message = 1; }

Live call

Message to send:

Ready.

Why gRPC-Web instead of native gRPC?

Browsers cannot use native gRPC because they don't expose low-level HTTP/2 framing control. gRPC-Web is a thin adaptation that works over regular HTTP/1.1 fetch() calls, using a 5-byte binary envelope per message. A server-side proxy (here: Node.js, in production: Envoy) translates between the two protocols.