Paddle Billing needs a notification destination per environment and creates none by default

Webhooks in Paddle Billing are configured as notification destinations, each carrying a URL, an explicitly selected list of event types and its own secret key shown only at creation. A newly created sandbox or production account has none, and there is no implicit delivery, so an integration that verifies signatures perfectly but was never subscribed simply receives nothing and looks like a broken gateway.

Event types are selected individually, so adding a handler branch for a completed transaction does nothing until that type is ticked on the destination. Destinations also offer a simulation feature that fires a chosen event type at your endpoint without a real transaction. Confirm by listing notification settings and diffing enabled types against your handler's branches. Recreate destinations when promoting to production, since the secret differs.