WebhookEnvelope

The event's payload, under the key the event names.

A billing event you can receive. billing-invoice-paid, billing-invoice-posted, billing-invoice-refunded, billing-checkout-created, billing-checkout-completed, billing-checkout-expired, billing-payment-succeeded, billing-payment-failed, billing-credits-depleted, billing-overage-incurred and billing-credit-cap-reached; each is described in the Webhooks section.

The delivery's ID (whd_…), the same on every retry of it: keep the IDs you've handled and ignore a delivery whose ID you've seen. A test delivery has an ID of its own.

true for a delivery sent with Send a test delivery, whose data is placeholder; false otherwise.

When the event happened, and the delivery was first queued; the same on every retry.