You change a button, the agent ships the diff, and now you want to see it on an actual phone screen. The old way: stop what you are doing, fire up ngrok, copy the random URL, paste it into your phone, and hope the tunnel does not drop. Every single time.

Shellular skips all of that. If the companion is running on your machine, your phone can already reach anything serving on localhost. Just type the address.

Type the address. That is the whole step.

Open the in-app browser in Shellular and enter your local URL the same way you would on your laptop: 

localhost:3000
localhost:5173
127.0.0.1:8080

The page loads. No tunnel to spin up, no public URL to generate, no firewall rule, no router settings. Because the Shellular app is already connected to your machine, your local ports are reachable from your phone over the same encrypted link.

It is not just a preview. It is a real browser with DevTools.

This is the part that makes it genuinely useful instead of a glorified screenshot. The in-app browser ships with real developer tools:

  • JavaScript console. See logs and errors, and run snippets, right from your phone.
  • Inspect tab. Poke at the DOM and styles to figure out why that layout is off.
  • Network tab. Watch requests, check payloads, and catch the call that is failing.

So when something only breaks on mobile, you are not stuck guessing. You debug it on the device where it actually happens.

Why this beats a tunnel

  • Nothing to set up. No ngrok account, no auth token, no per-port config.
  • Nothing exposed. A public tunnel puts your dev server on the open internet behind a shareable URL. Shellular traffic is end to end encrypted, so even the relay that connects your devices cannot read it, and your localhost stays private to you.
  • Nothing to babysit. No expiring URLs, no reconnects, no "tunnel session expired" right when you need it.
  • Any port, any framework. If it listens on localhost, you can open it.

The short version

Previewing and debugging a local dev server on your phone used to mean wrestling with ngrok or port forwarding. With Shellular, you type localhost:3000 into the in-app browser and you are looking at your site, with a console, inspector, and network tab right there. Private, instant, and zero setup.

And since the same app also runs your terminal and your AI agents, you can tweak code, ship it, and check it on a phone screen without ever getting up.