SNS : Simple Notification Service;

SNS : Simple Notification Service;

It is a web service that makes it easy to set up, operate and send notifications from the cloud.
It provides developers with a highly scalable, flexible and cost effective capability to publish messages from an application and immediately deliver them to subscribers or other applications.


SNS follows publish-subscribe messaging paradigm, with notifications being delivered to clients using a "push" mechanism that eliminates the need to periodically check or poll for the new information and updates.

With simple APIs requiring minimal up-front development effort, no maintainance, SNS gives developers an easy mechanism to incorporate a powerfull notification system with their applications.
 SNS -- PUSH ; SQS -- PULL/POLL;

 SNS can deliver notifications by SMS Text Messages or email, to SQS queues or to an HTTP end point.
 To prevent the messages from getting lost the SNS messages are stored across multiple availability zones.
 SNS allows you to group multiple receiptients using topics. Topic is an access point for allowing receiptients to dynamically subscribing for identical copies of the same notification.

 One Topic -- Multiple end points
        -- IOS devices
        -- Android devices
        -- SMS Receipients etc.,
        When we publish once to a topic SNS will deliver appropriately formatted copies of your message to each subscriber.
       
 SNS Benefits:
    -- Instantaneous, push-based delivery (no polling)
    -- Simple APIs and easy integration with applications
    -- Flexible message delivery over multiple tranport protocols.
    -- Inexpensive, pay-as-you-go model with no upfront costs.
    -- Web-based AWS Management Console offers simplicity of a point and click interface.
   
 SNS Vs. SQS
  -- Both messaging services.
  -- SNS -- Push
  -- SQS -- Poll/Pulls
 
 SNS Pricing
  -- $.50 for 1 million requests for SNS.
  -- $.06 per 100,000 notification deliveries over HTTP.
  -- $.75 for 100 notifications deliveries over SMS.
  -- $2.00 for 100,000 notification deliveries over Email.