protocol-lab:~$./run--all-paradigms
github ↗
$ cd ..

$ grpc --via connect▮

A typed Protobuf contract, generated into a Python server and a TypeScript client by buf. The browser calls it directly over Connect, with no proxy.

# steps
  1. 1Read the .proto contract.
  2. 2Run a unary call, then watch it serialize → POST → resolve.
  3. 3Start a server-stream and watch typed frames arrive.
  4. 4Open DevTools → Network to see a readable POST.
// the contract
proto3
syntax = "proto3";
package protocollab.v1;

service BoardService {
  rpc GetBoardStats(BoardStatsRequest) returns (BoardStatsResponse);
  rpc WatchBoard(WatchRequest) returns (stream BoardEvent);
}

message BoardStatsResponse {
  int32 total = 1;
  int32 todo = 2;
  int32 in_progress = 3;
  int32 done = 4;
  int32 members = 5;
}
message BoardEvent {
  int64 seq = 1;
  string type = 2;
  string task_id = 3;
}
// generated client
typescript
// generated by buf → board_service_connect.ts
import { createClient } from "@connectrpc/connect";

const client = createClient(BoardService);

client.getBoardStats(req): Promise<BoardStatsResponse>;
client.watchBoard(req):   AsyncIterable<BoardEvent>;
proto → types: the same contract drives the server and this client.
// unary · GetBoardStats
1
Typed request
2
Serialize
3
POST /rpc
4
Server
5
Typed response
→ sent · request frame
POST /protocollab.v1.BoardService/GetBoardStats
content-type: application/json
connect-protocol-version: 1

{
  "boardId": ""
}
← received · BoardStatsResponse (decoded)
// call the RPC to see the typed response
-
LATENCY MS
-
PAYLOAD BYTES
wire format
JSON: human-readable. Toggle to binary protobuf to shrink it.
// server-stream · WatchBoard
closed
// start the stream to watch typed BoardEvent frames arrive
Frames arrive when tasks change on that board - generate a task on the Real-time page or via REST. These are real BoardEvents from the server's EventBus.
No board yet - sign in & click “Create sample data” on Home to enable the unary call and the stream.
Same contract, two call styles: unary and server-streaming, both native in the browser, with no Envoy or grpc-web proxy.