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.

How does a dead-letter queue work?

A dead-letter queue lets you set aside and isolate messages that can't be processed correctly to determine why their processing didn't succeed. Setting up a dead-letter queue allows you to do the following: Configure an alarm for any messages delivered to a dead-letter queue.