Lineman

Lineman is a CLI collection runner for WebSocket requests.

It’s inspired by Postman Newman—Postman’s CLI runner for Postman collections—which primarily targets REST / request-response workflows. Lineman takes the same “run a collection from the terminal” approach, but is designed specifically for WebSocket interactions (connect, send, receive, and assert on messages).

Folder Structure

Lineman/
├─ src/
│  ├─ cli/
│  │  ├─ index.ts
│  │  ├─ types.ts
│  │  ├─ commands/
│  │  │  └─ run.ts
│  │  ├─ format/
│  │  │  └─ output.ts
│  │  └─ utils/
│  │     ├─ colors.ts
│  │     └─ errors.ts
│  ├─ runner/
│  │  ├─ index.ts
│  │  ├─ executor.ts
│  │  ├─ connection.ts
│  │  ├─ message-buffer.ts
│  │  ├─ assertions.ts
│  │  └─ types.ts
├─ collections/
│  └─ sample.json
└─ package.json

CLI

Build and link locally:

npm run build
npm link

Run a collection:

lineman run ./collections/sample.json

If file argument is missing:

Error: collection file required
Usage: lineman run <file>

Sample success output:

Running collection: Lineman Sample Collection

→ Test Request
   Connecting to wss://ws.postman-echo.com/raw
   SEND: Hello, WebSocket!
   RECEIVE: Hello, WebSocket! ✓

✓ Test Request passed

Summary:
1 passed, 0 failed