SQS allows users to specify a redrive policy for a particular queue. This policy describes what to do when a message fails to be consumed from a queue, including how many times to try to consume the message. It also allows you to specify a Dead Letter Queue, a queue that the message is sent to after it fails too many times. Specifying a redrive policy allows you to avoid “poison pills” (messages that cannot be handled and will clog up your consumer) and provides a place for failed messages to be stored for further inspection. Blue Matador alerts you when your dead letter queue is nonempty, as this queue is often configured and then neglected, resulting in failed messages that simply disappear without being addressed.