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Device preview

When a minion builds a web page, a screenshot only proves it rendered on the minion’s desktop, and VNC only shows you that desktop. Device preview gives you a URL you open on your own phone, so you review the real rendering, the real viewport and real touch behaviour.

Previews are created by the minion, not from the dashboard. The minion is the one that knows which port its dev server is on, so it registers the port and hands you back a URL. Ask for one in chat:

Start the dev server and share it as a preview.

The minion replies with a link. It can also share one on its own after finishing a piece of web work.

Open the minion — click it on the Minions page or in the office view — and go to the Preview tab, next to Chat, Terminal, Files and VNC. It lists everything that minion is sharing right now:

ButtonWhat it does
OpenOpens the preview in a new tab
Copy linkCopies the URL, for sending to your phone
Stop sharingRevokes the URL immediately

Each entry shows the port, the label the minion gave it, and how long it has left. The list refreshes on its own, so a preview registered while you have the tab open appears within a few seconds.

The URL works only for the owner of the minion, and only in a browser signed in to Minion. On a phone that has not signed in yet, you land on the login page first and are returned to the preview afterwards.

Passing the URL to someone else does not give them access — they get “This preview is not available”, the same page an expired link shows.

Expiry8 hours, counted from when the minion registered it
Concurrent previews3 per minion
PortsDev server ports only. The minion refuses its own runtime ports, and any port that nothing is actually listening on

Expired previews drop off the tab on their own, so there is nothing to clean up. Use Stop sharing when you want a URL dead before its time — it takes effect on the very next request, not when the link would have expired.

  • Hot reload is off. Previews are for review, so the minion starts the dev server with hot reload disabled — a dev server that keeps failing to reach its reload socket looks broken even when it is fine. Reload the page to pick up a change.
  • The first load can be slow. A dev server compiles the page on first request. The minion warms it up when it registers the preview, but a large page can still take a moment the first time.
  • A preview survives a restart of the dev server. As long as the minion re-registers the same preview, the URL you already have on your phone keeps working.
What you seeWhy
”This preview is not available”The link expired, someone pressed Stop sharing, or you are signed in as someone who does not own the minion
The login pageThe browser is not signed in to Minion. Sign in and you are returned to the preview
Blank page or missing stylesThe dev server is not serving that path any more. Ask the minion to check it is still running
The minion says it cannot share the portNothing is listening on it yet, or it is a port the minion runtime reserves for itself. Start the dev server first, then ask again