AWS SNS Amazon Simple Notification Service (SNS) is a fully managed pub/sub messaging service. Publishers send messages to topics, and subscribers receive them via SQS, Lambda, HTTP/S, email, SMS, or mobile push. It's the glue for fan-out architectures. Core Concepts - Topic — a logical channel for publishing messages - Subscription — an endpoint subscribed to a topic (SQS, Lambda, HTTP, email, SMS) - Message filtering — JSON policy to route only matching messages to a subscriber - Fan-out — one message published, delivered to all subscribers simultaneously - FIFO Topic — ordered, deduplicate…