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. It is how you find out whether the thing actually works.

Starting one

Run in sandbox sits under the Preview pane and acts on the last accepted checkpoint. It moves through a few states and each one is reported rather than hidden behind a spinner:

• 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 beside the button.
• Failed, with the reason, which is not the same as nothing having happened.

Sandboxes expire. That is deliberate: a sandbox is for looking at your project, not for hosting it. If you want something that stays up, that is publishing or your own deployment, covered in Taking your code with you.

Restarting after a change

A running sandbox keeps serving the checkpoint it was started from. Accepting a newer one does not change what it is serving, and the pane says so rather than letting the frame quietly misrepresent the project. Use Restart in sandbox to run the current one.

Stop shuts a running sandbox down. It does not touch share links, which are covered next.

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. That warning is in the interface next to the button, not buried in a tooltip, because it is the entire risk of the feature.

Two things worth knowing about how shares behave:

• Several can be active at once, each with its own expiry, each revoked independently. Revoking one does not disturb the others.
• They are not affected by restarting or stopping the sandbox. A share is a grant of access, tracked separately from the thing it grants access to.

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 in the Preview pane. It is currently the only place it appears: 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.