In this chapter, we covered the uses of messaging systems, the publisher and subscriber perspectives, and how to integrate them into applications. We also discussed multiple messaging patterns such as the queuing chain pattern, job observer, and priority queue.
We also used the simple notification service to produce fan-out to integrate into SQS and manage one-to-many communications.
In the third section, we introduced Amazon Cognito user pools and federated identities while explaining the use cases for each one. API Gateway is used to deploy a RESTful API with mock implementations.
Lastly, we covered WebSockets and which technologies are available in AWS to work with WS and best practices, and, finally, we looked at a web app showing how all the integration services discussed in this chapter can be used in a web application.