SQS-Lambda integration is fundamental to event-driven architectures on AWS. This article covers everything you need for production: partial batch response for selective retry, batching window tuning, visibility timeout calculations, DLQ strategies, message deduplication for FIFO queues, and how to handle poison messages. We include a SAM template showing recommended settings and a Node.js Lambda handler demonstrating the SQSBatchResponse pattern. Real-world edge cases like long-running jobs, downstream rate limits, and idempotency requirements are discussed in depth.