My app only works on my computer. How can other people use it?

If your app only works on your computer, that's normal while you build. The preview Claude Code gives you runs on your own machine, at an address only that machine understands. That's why it opens for you and nobody else, why it stops when your laptop sleeps, and why the same address fails on your phone. Here is each of those in plain words, and what changes when you put your app online.

Why the preview only opens for you

The preview address points at your own computer, so only your computer can open it. When Claude Code starts your app, it runs the app on your machine and gives you an address to open in your browser. That address is a special one that always means "this computer". Your browser asks your own computer for the app, and your computer answers.

Nobody else can use that address to reach you. If you send it to a friend, their browser looks for your app on their own computer, finds nothing, and shows an error. The preview also works only while your computer is awake and the app is still running on it. It's for trying things while you build.

Why your app works on your computer but not your phone

On your phone, the preview address means your phone, and your app isn't on your phone. It's the same reason the address fails for a friend. Being on the same Wi-Fi doesn't change that, because that address always points at the device you type it into.

If your app opens on your phone but looks squashed or broken, that's a different problem: the page probably wasn't laid out for small screens. Ask Claude Code to fix it on your computer first.

Make this app fit phone screens, and tell me what you changed.

Does your app stop when you close your laptop?

Yes, the preview does. Closing the lid usually puts a laptop to sleep, and the preview stops with it. It also stops when your computer restarts or shuts down, and when the app stops running on it.

You can set a laptop to stay awake with the lid closed, but people still can't reach it at the preview address.

So if you want to keep your website running when your computer is off, the preview can't do it. Your app has to run on a computer that's meant to stay on, which is what a host provides.

What putting it online changes

Putting your app online means a copy of it runs at a host, on a computer that isn't yours, and gets a link you can send. The original stays in your project folder, and you keep building with Claude Code as before.

What changes once it's online:

• Other people can open it. The link works on their phone or computer, wherever they are.
• It no longer depends on your laptop. Your computer can sleep without taking the online copy with it.
• It can remember things for everyone. If your app saves sign-ups or bookings, they have to be kept online, usually in a database, not in a file on your computer. Do I need a database for my app? explains when you need one.
• Its keys go with it. If your app uses a password or key, like a payment key, the host needs it too. Claude Code and your API keys explains where to put it.

Some tools give the preview on your computer a public link. They're handy for a quick look, but your computer has to stay on and awake the whole time.

To share an app you built with Claude Code, ask Claude Code to put it online, and name the host in the sentence so it knows which one you mean. How to put your Claude Code app online walks through every step. If you made your app in a chat instead, can Claude host my website? covers your options.

Where fline fits

I build fline. It's hosting for apps you build with Claude Code on your own computer: the place your app lives online, so other people can open it.

Once your account is open, you paste one line from your fline dashboard into your computer's Terminal app, and approve fline in your browser. Then, in your project folder, you tell Claude Code:

Put this project online with fline.

Claude Code packs up your project folder and sends a copy to fline. fline works out how to build and run it, so you write no setup files. Your app gets its own link with the padlock as soon as it's running, and the link opens on any phone or computer. Your app runs on a machine fline rents, not on your computer, so it doesn't depend on your laptop being open.

When you change your app, ask Claude Code to update it. The current version keeps running while the new one is prepared. You can also put your app at a web address you own, like www.yourbakery.com, and Claude Code can have fline create a database of your own.

What fline doesn't do yet: during the private beta, every app runs on one rented machine, with no spare. There's no uptime promise, and if that machine stops, your app is offline until it's back. That suits trying your app with your first users. fline also needs your project as a folder on your computer, sent by an AI coding app such as Claude Code. What fline does today lists what works and what doesn't yet, with a date on it, and your first launch, step by step shows the few steps that need you.

fline is free during the private beta, with no card. Claude Code's own plan is separate: when Claude Code puts your app online, that uses your plan as usual. We open accounts by hand, a few at a time.

Built your app with Claude Code, and want people using it? Ask for early access.

Questions people ask

Why does my app work on my computer but not on my phone?

The preview address Claude Code gives you always means "this computer". On your computer, that's where your app is running, so it opens. On your phone, the same address means your phone, and your app isn't there, so you get an error, even on the same Wi-Fi. For your app to open on a phone, a copy has to run online at a host, with a link that works on any device.

Does my app stop when I close my laptop?

The preview does. Closing the lid usually puts a laptop to sleep, and the preview stops until it wakes up. It also stops when your computer restarts or the app stops running on it. A copy of your app at a host doesn't depend on your laptop. On fline, your app runs on one machine fline rents. There's no uptime promise during the private beta, and if that machine stops, your app is offline until it's back.

How do I keep my website running when my computer is off?

You can't keep the preview running with your computer off, because the preview runs on your computer. To keep your app open to people, a copy has to run on a computer that's meant to stay on, which is what a host provides. With fline, Claude Code sends a copy of your project folder to fline, and your app runs on a machine fline rents. The original stays in your folder.

How do I share my Claude Code app with other people?

Put a copy online at a host and send people its link. Name the host when you ask Claude Code, so it knows which one you mean. With fline, once your account is open, you paste one line from your fline dashboard into your computer's Terminal app, approve fline in your browser, then tell Claude Code: Put this project online with fline. Your app gets a link that opens on any phone or computer.

Can I turn the preview address into a public link?

Some tools can give the preview on your computer a public link. Your computer still has to stay on, awake and connected the whole time, and the app stops when it sleeps or restarts, so it suits a quick look. For people to use your app whenever they like, put a copy online at a host instead. Then your app runs on the host's computer, not on yours.

Is my app private once it's on fline?

No. Your app's link is public, so anyone who has the link can open your app. If your app holds private information, like customers' names or orders, give it a sign-in, and ask Claude Code to check that each person can see only their own data. fline doesn't check your app's own code.