Why does Apps Script return 403, and how do I turn on the Apps Script API?

Who

Each builder, once. The Workspace admin only needs to know about it.

Time

30 seconds per builder

Google keeps one Apps Script setting outside the Admin console. Each user has a personal switch called Google Apps Script API at script.google.com/home/usersettings. While it is off, every call to the Apps Script API for that user returns HTTP 403, so the extension cannot create or deploy an app.

The extension detects this on first run. It probes the API once, and on the 403 it shows a card with the link. The builder flips the switch, comes back, and the extension re-checks when the tab regains focus. No sign-out is needed.

Turn it on

1. Open script.google.com/home/usersettings with your work account.
2. Set Google Apps Script API to On.
3. Go back to the extension.

The org-level question

We have found no Admin console setting that turns this on for everyone. The core-service toggle at Apps > Google Workspace > Apps Script must be on for the builders’ OU (see Prerequisites), but it does not flip the per-user API switch.

If your edition has an org-wide default we have not seen, tell us at the support address in the console and we will document it here.

What to tell builders

One line in your rollout message is enough: “The first time you open Applane it will ask you to turn on the Apps Script API at script.google.com/home/usersettings. That is expected; it is a Google setting, and it takes one click.”

The Apps Script 403 entry in the error reference covers the same thing from the builder’s side.