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When your app is running on localhost:3000, a Stably cloud browser cannot reach it directly because it is only available on your machine. Use a secure tunnel like ngrok to create a public HTTPS URL that forwards to your local server.

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1. Start your app

Run your app locally and confirm it is available at http://localhost:3000. 
npm run dev

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2. Start an ngrok tunnel

Install ngrok from ngrok.com/download, then run: 
ngrok http 3000
ngrok will print a forwarding URL like this: 
Forwarding  https://abc123.ngrok-free.app -> http://localhost:3000
Keep this terminal open while Stably runs your tests.

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3. Use the ngrok URL in Stably

Copy the HTTPS forwarding URL and use it as the target URL in Stably. For example, instead of testing: 
http://localhost:3000
test: 
https://abc123.ngrok-free.app
If your test starts on a specific route, append the route to the ngrok URL: 
https://abc123.ngrok-free.app/dashboard

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Tips

  • Restarting ngrok usually creates a new URL, so update the URL in Stably after each restart.
  • Keep both your local app server and the ngrok tunnel running for the full test run.
  • If your app uses OAuth callbacks, webhooks, or allowed origins, add the ngrok URL to the relevant allowlist while testing.
  • For local-only CLI runs on your own machine, you can still point tests directly at http://localhost:3000.

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Writing Playwright tests with Orca

You can also write Playwright tests in Orca, Stably’s open source agent IDE. Orca helps you work directly in your codebase, create or edit Playwright tests, and iterate against your local development server.