What is the purpose of the dead-letter queue (DLQ) in the reliability pattern?

• A. Dead Letter Queue (DLQ)
• B. Processing queue
• C. Discard
• D. Logs only

Answer: (A)

The dead-letter queue is a mechanism in the reliability pattern for handling messages that can’t be processed after retries. When a message keeps failing, it’s moved to this separate queue instead of being lost or discarded, so you can inspect the payload and the error, diagnose the root cause, and decide how to remediate—often reprocessing later or routing to manual intervention. This preserves data, supports auditing, and keeps the main processing flow resilient.

The other options don’t fit: a processing queue is just the normal queue for ongoing work, discarding would lose the failed message, and logs only would provide visibility without offering a path to reprocess or remediate.