Operations

A queue is a stream the platform drains internally. Webhook delivery is the first; the list is discovered rather than declared, so a queue this documentation has never heard of will still appear.

This is an operator surface. It describes the estate rather than any one merchant, and is not scoped to one, which is why it is administrator-only. A merchant asking whether its webhook arrived is asking about a delivery, and that is on the subscription, under /webhooks/{webhookId}/deliveries.

A read is a live measurement, not a stored record: nothing is kept and asking twice gives two answers.

backlog and lagSeconds are the two numbers to watch, and they say different things. A backlog is how much is waiting; a lag is how long it has been waiting. A queue with a large backlog and no lag is busy and keeping up. A queue with a small backlog and a growing lag has something stuck at the front of it.

members and silentMembers are a pair, and the second is the interesting one. A member registers when a process starts and is only removed when something asks, so a process that dies leaves its registration behind until it is swept. silentMembers is how much of members is residue rather than capacity.

A dead letter is a message a consumer could not handle, kept exactly as published. Replaying one puts it back on the queue unchanged, to be offered to whoever is draining; it is the fix, not a note that the fix is needed. Replay is safe to repeat: a consumer that still cannot handle the message will dead-letter it again rather than stop.