A specialized service queue storing messages that could not be processed successfully due to errors or schema invalidity.
A Dead Letter Queue (DLQ) is an architectural pattern that routes malformed, corrupted, or repeatedly failing messages to a segregated topic for forensic inspection, preventing poisoned payloads from blocking message consumption pipelines.
Used across Strimzi Kafka topics (`*.dlq.v1`) to capture unparseable IoT telematics, corrupted EDI messages, or failed blockchain commit requests with Base64 payload snapshots for SRE review.
Messages failing 3 retry backoff attempts are forwarded to `[topic].dlq.v1` with headers recording failure timestamp, error stack, retry count, and original partition offset.
Routing to a DLQ quarantines failure; it does not automatically resolve the underlying bug or recover the failed transaction.