Lesson 1.2 (CLI track): Multi-protocol — REST + gRPC

Difficulty: Beginner | Duration: 10 min | Prerequisites: Lesson 1.1

Overview

Add a gRPC service alongside the REST one from Lesson 1.1 and watch them light up in the same workbench. The trick: --url is repeatable — one CLI invocation, two backend URLs, one workbench.

You'll also fire your first server-streaming call and watch frames arrive live in the workbench's stream pane.

Steps

1. Keep the REST API running

If the Lesson 1.1 sample (HelloApi on localhost:5001) is still up, leave it. Otherwise restart it:

cd units/unit-1-samples/HelloApi
dotnet run

2. Start the gRPC service in a second terminal

cd units/unit-1-samples/HelloGrpc
dotnet run

Output:

Now listening on: http://localhost:5002
Application started. Press Ctrl+C to shut down.

The service registers two methods on the greeter.Greeter service:

Hello — unary, returns one greeting.
HelloStream — server-streaming, emits N greetings one per second.

It also enables gRPC Server Reflection, so Bowire's gRPC plugin can discover the service shape without you having to upload the .proto file.

3. Point Bowire at both URLs at once

In a third terminal:

bowire --url http://localhost:5001 --url http://localhost:5002

--url is repeatable. Each plugin probes both URLs; whichever protocol matches each URL claims it. The sidebar ends up with two top-level entries:

🔌 HelloApi (REST)
   └─ GetGreeting
   └─ PostEcho
   └─ GetHealth
🟢 greeter.Greeter (gRPC)
   └─ Hello              (unary)
   └─ HelloStream        (server-streaming)

4. Invoke the gRPC unary method

Click Hello under greeter.Greeter. The form is built from the proto schema: a string name field, an int32 count field (unused for unary; ignore it). Fill name = "Bowire", click Invoke.

You get a single response:

{
  "greeting": "Hello, Bowire!",
  "receivedAt": "2026-06-01T08:30:14.1234567+00:00"
}

5. Fire the streaming method

Click HelloStream. Fill name = "Bowire", count = 5, click Invoke.

The response pane switches into stream mode and shows frames arriving live, one per second:

[#1] { "greeting": "Hello 1/5, Bowire!", "receivedAt": "..." }
[#2] { "greeting": "Hello 2/5, Bowire!", "receivedAt": "..." }
[#3] { "greeting": "Hello 3/5, Bowire!", "receivedAt": "..." }
[#4] { "greeting": "Hello 4/5, Bowire!", "receivedAt": "..." }
[#5] { "greeting": "Hello 5/5, Bowire!", "receivedAt": "..." }

After the fifth frame the stream closes and you see the total duration.

6. Switch between the two services

Both services are alive in the same workbench — clicking back into REST methods works without re-pointing or restarting. That's the headline: REST and gRPC share the same UI primitives (sidebar, invoke pane, response viewer, recording recorder), so a polyglot service mesh is one workbench, not five tabs.

Key Takeaways

--url is repeatable. Pass it as many times as you have services to wire up. Auto-discovery sorts out which plugin claims which URL.
Same UI for unary and streaming. The response pane shape changes; everything else stays put.
gRPC discovery via reflection. No .proto upload, no manual service descriptor — AddGrpcReflection() + MapGrpcReflectionService() on the server side tells Bowire everything it needs.
Polyglot service mesh = one workbench. Across any combination of bundled / installed protocols (REST + gRPC + GraphQL + MQTT + SignalR + &c.) — --url keeps being repeatable; auto-discovery scales linearly with services.

What's Next

Both setup tracks merge here. From this point on, the workbench UI is identical regardless of how Bowire got mounted — so the rest of the bootcamp is shared.

Continue: → Unit 2: Record, Replay, Mock

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