It provides a low-cost infrastructure for mass message delivery for mobile users.

SQS – Simple Queue Service.

This is an Amazon-managed queuing service that makes it easy to decouple and scale microservices or distributed systems or serverless applications.

Using SQS, you can send, store, and receive messages between software components at any volume, without losing messages or requiring other services to be available.

It is a web service that makes it easy to set up and operate and send notifications from the cloud. It provides the capacity to publish messages from an application and immediately deliver them to subscribers or other application.

SNS – Push notification to mobile devices

Also has SMS text Capability

SNS can trigger email, HTTP, Lamda functions.