You cannot send a localhost link. How to share an app that only opens on your computer

No. A link that starts with http://localhost or http://127.0.0.1 only works on the computer where the app is running. "localhost" is not a website, it is the name every computer gives to itself. When your boss opens it on their laptop, their browser looks for the app on their own machine, finds nothing, and shows an error. Nothing is broken; the link was never meant to travel.

This page explains why that happens, what the two real options are (a tunnel for a ten-minute demo, or a deployment for something people will keep using), and how to do the second one from Claude Code without learning the vocabulary.

Why the link does not work for anyone else

When Claude Code says "your app is running at http://localhost:3000", it means: a small server is running on this computer, on door number 3000. Two things follow from that:

1. The address is relative to whoever reads it. localhost on your machine is your machine. localhost on your coworker's machine is theirs. The same URL points to two different computers.
2. The app only exists while your computer runs it. Close the terminal, put the laptop to sleep, or lose Wi-Fi, and the app is gone even for you.

So the question is not "how do I send the link", it is "how do I put the app somewhere that is not my laptop". There are two ways to answer that, and they solve different problems.

Option 1: a tunnel, for a quick demo

Tools like ngrok, Cloudflare Tunnel or localtunnel open a temporary door from the public internet to the app on your computer, and give you a random URL such as https://a1b2-203-0-113-5.ngrok-free.app. That is the right tool when you want to show something for ten minutes on a call.

What it does not do:

• The link dies when your computer sleeps. The app is still running on your laptop; the tunnel only forwards traffic to it.
• The free URL changes every restart, so you re-send the link every time. A fixed address is a paid feature.
• Anyone with the URL gets in, and visitors on free tiers usually see a warning page before the app.
• It needs a terminal, an account, a token, and knowing which port your app uses.

If the goal is "my team uses this every day", a tunnel is the wrong shape. You would be running a server out of your laptop indefinitely.

Option 2: deploy it, so it lives on its own

"Deploying" means copying the app to a computer that is always on, in a data center, with a permanent public address. After that the app runs without you. This is what platforms like Vercel, Netlify, Railway or Render do, and each of them assumes you know Git, a terminal, build commands and environment variables. If you built the app by describing it to Claude Code, that vocabulary is exactly what you do not have.

White Ghost is a deployment platform built for that situation. Here is what the flow looks like when the person doing it is the same person who never wants to read a build log.

Step by step from Claude Code

1. Create the app. In your terminal, in the folder Claude Code has been working in, run ghosty init. It creates a repository in your own GitHub account and registers the app. You need a GitHub account for this (that is where your code lives, so it stays yours).
2. Let the assistant do the technical part. Every White Ghost app has "Open in Claude Code" and "Open in Codex" buttons, plus "Copy the instructions", which hands the assistant a ready-made prompt with the app URL and the repository URL. Paste it, and Claude Code moves your project into place and pushes it.
3. Every push goes live. There is no separate publish step. Real builds on a full app with a frontend and a backend have taken 53 seconds and 1 minute 27 seconds. If a build breaks something, ghosty rollback or the Redeploy button on any earlier build puts the previous version back.
4. Share a permanent address. The app gets its own URL that does not change and does not depend on your computer. If you own a domain, you can point it at the app and the certificate is issued and renewed for you.

Decide who can open it

This is the part a tunnel never gives you. When you create the app you choose an access mode:

• Public: anyone with the link.
• A shared invite code: people need a code you hand them. It is one code for everyone, not a list of named guests, so treat it like a shared password.
• Your own sign-in: the app asks for a login you write into it, for example with Claude Code's help.

The mode is part of the app's code, so changing it later means editing and redeploying rather than flipping a switch.

What else comes with it

Most apps built with an assistant need more than a web page: somewhere to store data, a place for uploaded files, a secret API key or two. A White Ghost app includes a managed PostgreSQL database, file storage that is added when your code needs it, secrets you paste once in the console, and scheduled jobs. The console lists the nine pieces it manages for you, with the status of each, so you can see what you did not have to set up.

Honest limits

• White Ghost runs Node and Python apps. A plain HTML file is not an app by itself; Claude Code can wrap it into one in a few minutes.
• The app scales to zero when idle, so the first visit after a quiet period takes a moment to wake up.
• You need a GitHub account, because the code is stored in your account and you can download it as a zip whenever you want.
• Preview links for pull requests are public URLs; do not put production data behind a preview.

Which one should you pick

If you are on the second row or below, run ghosty init and hand the rest to Claude Code.

Frequently asked questions