Achieving loose coupling with Events
Amazon SQS, SNS, DynamoDB Streams, Kinesis Streams, Lambda.
With the event driven architecture, two systems don’t need to know about each other. Each of them can fire events while the other responds to that specific event.
SNS has publish/subscribe model. When publisher pushes, all subscribers immediately get the message. This can be email, SMS, SQS, Lambda etc.
SQS queuing for delivery method. Messages are persisted until they are polled. Extremely scalable. Can potentially contain millions of messages.