DLQ

DLQ (Dead Letter Queue, or Dead Letter Topic in Kafka's vocabulary) is a dedicated topic where messages that repeatedly failed processing are published, after retry attempts are exhausted. Kafka has no native DLQ mechanism like SQS does — it's implemented by the application (or by a framework, like Spring Kafka via DeadLetterPublishingRecoverer), publishing the problematic message to a separate topic. The main benefit is isolating the "poison pill" effect: a message that gets stuck doesn't block the rest of that partition's messages indefinitely.