The demo that dies when the lid closes.

Some work should be shown while it is still running on your machine. The mistake is using that live tour as the only copy of the app.

Two ways to show the same URL

A static publish takes the files you have right now and serves them from a public address. Refresh tomorrow and you get those files, whether or not your laptop is on. That is the right artifact when the page is ready to be looked at alone.

A tunnel takes that same public address and, for a while, forwards it to a server on your computer. The person on the call clicks a normal HTTPS link. The response is coming from localhost, often port 3000 or 5173, wherever the dev server actually is. You can change a component, save, and they see it without you deploying again. When you stop the tunnel, the address should fall back to the last static publish, not to an error.

Those are different jobs. The tunnel is a presentation. The static publish is the thing that remains. Projects get stuck when the presentation is the only thing that was ever set up.

When the live path is the right path

• The UI depends on a dev server, hot reload, or a local-only API you are not ready to host.
• You expect to edit during the conversation. Deploying after every sentence would waste the meeting.
• The person needs to click it themselves, and they are not on your wifi. Screen sharing shows your screen. A tunnel shows their browser.

Start the local app first, then open the tunnel, then send the link. If you send the link before the dev server is listening, the visitor arrives at a connection error and decides the project is broken. Tell them the link is live only while you are both in the room. That expectation is part of the demo.

What has to be true after the call

People forward links. They also reopen them the next morning, when your laptop is in a bag. If the only version of the app is the tunnel, that morning visit fails, and the project looks abandoned. Before you hang up, check three things:

1. There is a static publish on the same address, even if it is a simpler build than the live dev server.
2. You know what the visitor will see once the tunnel stops. Open the URL yourself after you stop it, from a phone on cellular if you can.
3. Anything they submitted during the demo is stored somewhere that is not the memory of the dev server. A form that only appends to a local array will be empty when they come back.

The failure mode to watch

The dangerous demo is the one that feels successful. They clicked, they smiled, they said they would look again tonight. Tonight the DNS still resolves and nothing is listening. From their side the project died. From your side you only closed a laptop. Publish the files before you need the applause to last until morning.