Dead Letter Queues: Handling Poison Messages in SQS, RabbitMQ, and Kafka

Learn to isolate messages that always fail without blocking your pipeline: transient vs permanent errors, retry limits with backoff, terminal DLQs, error metadata and controlled reprocessing. Expanded edition: SQS with Lambda and partial batches, programmatic redrive, backoff via ChangeMessageVisibility, RabbitMQ 4 quorum queues (delivery-limit and at-least-once dead-lettering), non-blocking retry topics in Kafka, Spring and Kafka Connect, SNS/EventBridge, deserialization and schemas, idempotency with an inbox table, observability with CloudWatch and Prometheus, testing with Testcontainers and LocalStack, security and retention, multi-tenancy, KEDA autoscaling, an operational runbook, a full case study and FAQ. With production-ready Python code.

36 minutes read

2026-07-27

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