Start UI mode from the project root: npx playwright test --ui
The interactive runner opens in a browser window; select tests from the left panel to run them individually or as a group
Enable watch mode by clicking the eye icon next to a test file; Playwright re-runs the test automatically on every file save
Click any step in the timeline to time-travel to that point and inspect DOM state, network requests, and console logs
Use the Pick Locator button to click an element on the live preview and copy its stable Playwright selector to your test file
Run in headless CI by omitting --ui; the same test suite works without modification in both modes
Known gotchas
Playwright UI mode is only available in the Node.js runner; it is not supported in the Python, Java, or .NET bindings
UI mode launches a local web server on a random port; firewall rules or port conflicts on the CI host can prevent the server from starting even when --ui is not intentionally passed
Time-travel debugging replays from a Playwright trace captured during the run; if tracing is disabled in playwright.config.ts, the timeline will show no step details
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