Term Kind Topic What it is
At-Least-Once Delivery Redelivery Semantics, Duplicate-Tolerant Delivery concept Webhooks The delivery guarantee that a message will arrive but may arrive more than once - the strongest practical guarantee across an unreliable boundary, which pushes the deduplication responsibility onto the receiver.
Webhook Retry Policy concept Webhooks The provider's schedule for re-attempting failed deliveries, and the contract the receiver must be built against.