Amazon Simple Notification Service (SNS)
Amazon SNS was launched in 2010 and it is a fully managed serverless service offering the publisher/subscriber pattern with a push mechanism for sending messages to subscribers. Similar to Amazon SQS, Amazon SNS provides a highly scalable, available, and elastic service that can be used for decoupled architectures.
Amazon SNS uses the concept of topics. Topics are logical entities used to denote a specific category, subject, or type of event. The topic forms an "access point" of the service. Subscribers can subscribe to one or more topics of interest and get messages, and publishers send messages to their topics of interest. Amazon SNS identifies the list of subscribers for a particular topic and then delivers the messages sent to those topics to the corresponding list of subscribers. Unlike SQS message queues, where messages are received by one consumer, SNS messages are delivered to all subscribers in a process called fan-out...