What localhost actually is
When your agent says the app is running at localhost:3000 or localhost:5173, it means running on this computer, for this computer. The word is a nickname every machine uses for itself. So when you send that link to a friend, their computer looks for the app on itself, finds nothing, and shows an error. Nothing is broken. The app was simply never anywhere else.
Close the laptop, and it stops for you too.
What has to happen instead
The app needs to live on a computer that is always on and that everyone can reach, with an address that means the same thing everywhere. That used to be a project of its own: choosing a host, setting it up, keeping it running, and then adding sign-in and saving on top, because an app that people share needs to know who is who.
Tiniest Cloud is that computer, with those parts already in it.
The one sentence
Connect your agent to Tiniest Cloud once. It takes about two minutes and is described on the start page. From then on, in the same chat where you built the app, say:
Put this on Tiniest Cloud.
Your agent uploads the app and tells you its address, something like myapp.tiniest.cloud. That link works on any phone, anywhere. Send it to anyone.
What people see when they open it
Your app, with a sign-in already in front of it. They use an email link or their Google account; there are no accounts for you to make and no passwords for anyone to keep. Whatever they add is saved, and each person sees their own things unless you decide the app is shared. If you change the app later, the new version goes live the same way, and every old version is kept in case you want it back.
No agent?
If you built the app another way, sign in to app.tiniest.cloud and drag the folder onto the page. Same address, same sign-in, same saving.
