Pattern 24 / RESILIENCE

Dead Letter Queue (DLQ)

Use this when stopping poison messages from blocking the main queue forever.

Pressure
Stopping poison messages from blocking the main queue forever
Mechanism
After retries are exhausted, move the failing message to a separate queue for inspection
Toll
Dlqs need ownership, alerts, replay tooling, and cleanup
Architecture plate24
Diagram for Dead Letter Queue (DLQ)
Executive brief

Dead Letter Queue (DLQ) fits when stopping poison messages from blocking the main queue forever. Mechanism: after retries are exhausted, move the failing message to a separate queue for inspection. Use it for message-driven systems, ETL, event consumers, and background jobs. The toll: DLQs need ownership, alerts, replay tooling, and cleanup.

Use when

Message-driven systems, etl, event consumers, and background jobs.

Example

Malformed invoice job moved to dead-letter queue after five failures.

Review framing

Describe the pressure first, then the mechanism, then the cost. That keeps the design grounded.

Same pressure family

Reliability Patterns

19Circuit Breaker20Retry with Exponential Backoff21Bulkhead22Timeout23Idempotency25Graceful Degradation
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