Using T3 Code from a phone or tablet
No App Store build, but T3 Code runs in a mobile browser over Tailscale. How to pair by QR code, and what actually works on a phone-sized screen.
Short version: there is no native App Store or Play Store app. T3 Code's front end is a web app, and a mobile browser can connect to a server running on your desktop. In practice that covers most of what people want from a phone.
Why this works at all#
The desktop app and the browser UI are the same React front end talking to the same Node server over WebSocket. Nothing about that requires a desktop browser. Point Safari or Chrome on your phone at a running server and you get the real interface — threads, streaming output, diffs.
The agent runs on the host machine, with the host's repositories and credentials. Your phone is a screen.
Setting it up#
1. Start a server on the machine that has your code.
npx t3 serve --host "$(tailscale ip -4)"Or with Tailscale terminating HTTPS, which is the better experience on mobile:
npx t3 serve --tailscale-serve2. Scan the QR code. t3 serve prints one along with the URL and pairing token. Scanning is substantially less painful than typing a pairing token on a phone keyboard.
3. Add it to your home screen. In Safari, Share → Add to Home Screen; in Chrome, menu → Add to Home screen. You get an icon and a full-screen view without browser chrome, which makes a real difference on a phone-sized viewport.
What's actually usable on a phone#
Honest assessment, based on what a touch screen is good at:
| Task | Verdict |
|---|---|
| Reading agent output | Good |
| Kicking off a thread from a short prompt | Good |
| Checking whether a long run finished | Good — the main use case |
| Approving Supervised prompts | Workable |
| Reviewing a small diff | Workable |
| Reviewing a large diff | Painful |
| Writing a detailed prompt | Painful |
| Resolving conflicts, merging | Don't |
The realistic pattern is monitoring and nudging: you start a long refactor at your desk, walk away, and check on your phone. Recent builds have been polishing exactly this — there's an iOS git progress overlay and thread snoozing, which suggests mobile is getting deliberate attention.
Keeping the host awake#
The most common mobile disappointment isn't the UI, it's coming back to a dead session because the host machine slept.
- macOS — disable sleep, or run
caffeinatealongside the server - Windows — set the power plan to never sleep while plugged in
- Linux — mask the sleep targets, or just use a machine that doesn't suspend
A cheap always-on Linux box or a home server is the setup that makes mobile access genuinely useful.
Security, briefly#
Your phone will store a pairing token that grants shell access to your development machine. That raises the stakes on the phone itself: keep a device passcode, and revoke the token with t3 auth if the phone is lost or sold.
Don't pair over hotel or coffee shop Wi-Fi to a server on a public IP. Tailscale, or nothing.
FAQ#
Is there a T3 Code iOS app?#
There is no native App Store app. T3 Code's web interface works in mobile Safari, and you can add it to your home screen for a full-screen, app-like experience. It connects to a server running on your computer.
Can I use T3 Code on Android?#
Yes, through Chrome or any modern mobile browser connected to a T3 Code server on your computer. Add it to your home screen for a standalone window.
How do I connect my phone to T3 Code?#
Run npx t3 serve --tailscale-serve on your computer and scan the QR code it prints. Both devices need to be on the same Tailscale network, or the same LAN if you're using a local address.
Is T3 Code usable on a phone screen?#
For monitoring runs, reading output and sending short follow-ups, yes. Reviewing large diffs and writing detailed prompts are much better on a desktop.