How to share a localhost app with other people
Your app runs on localhost but nobody else can open it. Here is how to give it a real link, keep it private and not leave your laptop on.
An app on localhost only exists while your computer is on and only for you. To share it, it has to run somewhere that stays up and has an address.
Why localhost cannot be shared
localhost means “this computer”. The address 127.0.0.1 or localhost:3000 points at your own machine, so a teammate typing it reaches their own computer, not yours.
Three ways people try, and the catch
- A tunnel (such as a temporary public URL to your laptop): quick for a demo, but it dies when you close the lid.
- Sending the files: the other person needs the same tools installed and set up.
- Hosting it: the only option that keeps working when your computer is off.
Put it on a host in four steps
- Upload the folder, a .zip or a GitHub repo, or ask your assistant to deploy it over MCP. Cohostly shows draft settings first, and nothing goes live until you confirm.
- Check the start command and port. The app should read its port from the PORT variable instead of a fixed number.
- Move keys out of the code and add them as secrets.
- Choose who can open it: named people by email, your team, anyone with the link, or the public.
What to check before you share
Run it once from a clean folder, make sure no file path points at your own computer, and confirm the app does not need a local database file that will not travel with it.
Questions
How do I make my localhost app public?
Deploy the project to a host and share its link. A tunnel works for minutes; a host works all week.
Can I share it with only one person?
Yes. On Cohostly you share by email with named people, and nobody else can open the link.
Does my computer need to stay on?
No. Once deployed, the app runs on the host, and rests when idle.