Sns

• Highly available PubSub service
• SNS is a AWS Public service
• Co-ordinates sending & receiving messages of upto 256kb size
• Base entity is SNS Topics on which permissions are given & configurations defined
• Publisher sends message to a topic
• Subscribers subscribe to a topic. A message sent to a topic is received by subscribers
• Subscribers could be HTTP Endpoints, email addresses, SQS, Mobile Push notification systems, SMS,Lambda
• Filters can be applied by subscribers to only receive certain messages based on a criteria
• Fanout architecture can be created by having multiple SQS queues as subscribers
• SNS offers delivery status wherever supported
• SNS offers delivery retries
• It is regionally resilient service & is highly available across AZs
• It supports SSE.

• Topic Policy can be used for cross account access