Amazon Simple Notification Service (SNS) is a cloud service for coordinating the delivery of push messages from software applications to subscribing endpoints and clients. All messages published to Amazon SNS are warehoused across several availability zones to prevent loss.
Amazon SNS allows users to push messages to Windows, Google, Apple and certain internet-connected smart devices by using an application programming interface (API) or the AWS Management Console. Once a message is published to the service, it can be sent multiple times to different recipients. Service users also have the flexibility to send direct messages to several devices or to one subscriber by using a sole publish request.
To get started with Amazon SNS, developers first have to create a topic, which is an access point for subscribers who are interested in receiving notifications about a specific subject. Developers publish a message to a topic when they have an update for subscribers and this action prompts Amazon SNS to distribute the message to all appropriate subscribers.
Amazon SNS has pay-as-you-go-pricing and no upfront costs. Users who sign up for AWS Free Tier receive 1 million mobile push notifications. Topic owners are able to set policies specifying which types of protocols will be supported. They can also be used to limit who can subscribe to notifications or publish messages. The subscribers, who are also called clients, can choose how notifications will be delivered.