The Simple Notification Service, or SNS for short, is one of the central services to build serverless architectures in the AWS cloud. SNS itself is a serverless messaging service that can distribute massive numbers of messages to different recipients. These include mobile end-user devices, like smartphones and tablets, but also other services inside the AWS ecosystem.
SNS’ ability to target AWS services makes it the perfect companion for AWS Lambda. If you need custom logic, go for Lambda; if you need to fan out messages to multiple other services in parallel, SNS is the place to be.