In message queueing the dead letter queue is a service implementation to store messages that meet one or more of the following criteria: Message that is sent to a queue that does not exist. Queue length limit exceeded. Message length limit exceeded. Message is rejected by another queue exchange.

What is a dead-letter queue?

A dead-letter queue (DLQ), sometimes referred to as an undelivered-message queue, is a holding queue for messages that cannot be delivered to their destination queues, for example because the queue does not exist, or because it is full.

What is the purpose of a dead-letter queue?

The dead-letter queue (or undelivered-message queue) is the queue to which messages are sent if they cannot be routed to their correct destination. Messages are put on this queue when they cannot be put on the destination queue.