Can an external system be notified via Webhook once a record has been approved?

Yes, with one extra step on your side.

Add a webhook for record.updated on that Base. Whenever a change to a record there is approved, Busabase sends the record's current field values, including your status field. Your system then checks whether the status is now "Approved" and acts on it.

Two things to know: a webhook can't be set to fire only when a field reaches a specific value, and it doesn't include the previous value. If you need to react only at the moment a record switches to Approved, keep the last status you saw for each record and compare when a notification arrives.