SNS and SQS: Messaging and Decoupling Services

SNS and SQS are messaging services that help decouple application components. Simple Notification Service is for pub/sub messaging—you send a message to a topic, and multiple subscribers get it. Simple Queue Service is for decoupling—you send messages to a queue, and consumers poll them. I built an image processing system where uploads to S3 trigger an SNS topic, which fans out to SQS queues for different processing steps. This architecture makes systems more resilient. If a component fails, messages wait in the queue.