AWS service to setup, operate and send notifications from the cloud.
Provides developers with highly scalable, flexible and cost effective capability to publish messages from an application and deliver them to subscribers or other applications.
Can have push notifications from all your devices - Apple, Google, Fire OS ,Windows and android devices.
Apart from pushing cloud notifications directly to mobile, you can deliver notifications by sms text messages or email to Amazon SQS queues or to any Http Endpoint.
SNS notifications can also trigger lambda functions (subscribed to SNS topic), with payload of published message.
Lambda can perform operation on payload, publish message to another SNS topic or send message to other AWS service.
SNS Topics
Allows to group multiple recipients using topics.
A topic is an “access point” for allowing recipients to dynamically subscribe for identical copies of the same notification.
One topic can support deliveries to multiple endpoint types - you can group together IOS, Android and SMS recipients. When you publish once to a topic, SNS delivers appropriately formatted copies of your message to each subscriber.
To prevent messages from being lost, all messages published to SNS are stored redundantly across multiple availability zones.