Running and sharing your project

A sandbox is a real, installed, running copy of your project: a dependency install and a dev server, not a rendering of the plan.

Starting one

Run live preview sits in the Preview tab once something is built, and runs the project’s current code, including a build that is still being checked. It reports each state it moves through:

• Queued, with your position, when every sandbox is busy.
• Installing dependencies, which is usually the slow part.
• Starting the dev server.
• Ready, at which point the frame is the running app and the expiry time is shown below it.
• Failed, with the reason.

Sandboxes expire: after ten minutes without use, and thirty minutes after starting whatever happens. You have one at a time, so opening another project stops it. On the Free plan, new previews stop starting once two hours of the day are used (one already running finishes), and a Free preview can wait in the queue while a few sandboxes are kept for paid plans. A sandbox is for looking at your project, not hosting it. For something that stays up, publish it or deploy it yourself: see Taking your code with you.

When the project changes

A running sandbox picks up each new version of the project in place. The tab says Updating preview… while the changed files go in, and the page reloads. When a change touches the project’s dependencies, they are installed first and only the dev server is restarted. When the sandbox cannot take a change in place (it has expired, or an update broke off), the builder restarts it and says why beside the preview. Restart stays on offer.

Stop shuts a running sandbox down. It does not touch share links.

Sharing what is running

Share mints a link to the running sandbox. Anyone with that link can view the running app and everything it shows, until it is revoked or expires. The builder shows that warning next to the button.

How shares behave:

• Several can be active at once, each with its own expiry, each revoked independently.
• They are not affected by restarting or stopping the sandbox.
• Each lasts 24 hours at most, and never longer than the preview it points at.

This is not the project’s own share link, the one under Share in the top bar, which shows the project’s code and lets somebody remix it. See The builder, pane by pane.

If your project shows real data, a share shows real data. Load it with something you would be comfortable sending to whoever you are sending the link to.

When a sandbox fails

The failure reason appears only in the Preview tab: install, build and type errors from a sandbox run are not reported under Problems yet, and the sandbox’s process output is not piped into the Console. See The builder, pane by pane.