Sqs

You'll use this when you need reliable async communication between systems, whether that's microservices, Lambda functions, or distributed workers. The skill covers both standard queues (high throughput, at-least-once delivery) and FIFO queues (strict ordering, exactly-once). It walks through dead-letter queue setup, visibility timeout management, and Lambda event source mappings with actual CLI commands and Python examples. The long polling and batch processing patterns are solid. One thing to know: FIFO queues have lower throughput limits (300-3000 msgs/sec depending on batching), so standard queues are usually the default choice unless you absolutely need ordering guarantees.