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2026-07-29 16:01
WebSocket

WebSocket Connection

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Try Interactive Demo

What you will learn

  • Test the full handshake: 101 Switching Protocols, Sec-WebSocket-Accept header — not just open event
  • Authenticate via query param or subprotocol — cookies may be blocked by the browser
  • Test reconnection with exponential backoff — the protocol is stateless about retries

Description

Establish a WebSocket connection to an echo server and verify the connection is open.

Test Scenario

// Test: Verify connection establishment
const ws = new WebSocket('wss://echo.websocket.org');
await waitFor(() => ws.readyState === WebSocket.OPEN);
expect(ws.readyState).toBe(WebSocket.OPEN);
ws.close();

Testing Tips

  • •Use WebSocket constructor with wss:// URL
  • •Listen for the onopen event
  • •Check readyState === WebSocket.OPEN
// Playwright API Testing - WebSocket
import { test, expect } from '@playwright/test';


test('WebSocket connection', async ({ page }) => {
  // Listen for WebSocket connections
  const wsPromise = page.waitForEvent('websocket');


  await page.goto('/websocket-demo');


  const ws = await wsPromise;
  expect(ws.url()).toContain('ws://');


  // Wait for message
  const framePromise = ws.waitForEvent('framereceived');
  const frame = await framePromise;
  expect(frame.payload).toBeDefined();
});

Challenge ID: ws-connect

2 frameworks available