Amazon SQS / SNS

SQS provides reliable message queuing, SNS provides pub/sub — together they cover most async communication patterns. Dead-letter queues, visibility timeouts, and FIFO ordering handle the edge cases that trip up simpler solutions.

Use SQS for work queues where each message needs exactly-once processing. Use SNS for fan-out where multiple subscribers need the same event. The combination is straightforward and eliminates the need for self-managed message brokers like RabbitMQ.