Simple Queue Service (SQS)
Messaging queue; store and forward patterns
Building distributed / decoupled applications
Simple Notification Service (SNS)
Set up, operate, and send notifications from the cloud
Send email notification when CloudWatch alarm is triggered
Step Functions
Out-of-the-box coordination of AWS service components with visual workflow
Order processing workflow
Simple Workflow Service (SWF)
Need to support external processes or specialized execution logic
Human-enabled workflows like an order fulfilment system or for procedural requests
Amazon MQ
Message broker service for Apache Active MQ and RabbitMQ
Need a message queue that supports industry standard APIs and protocols; migrate queues to AWS