Which service would you use to send alerts based on Amazon CloudWatch alarms?

Using Amazon Simple Notification Service (SNS) to send alerts based on Amazon CloudWatch alarms is a key aspect of monitoring and responding to system events in AWS. When you set up a CloudWatch alarm, it can trigger an SNS notification when the alarm state changes, such as moving to "ALARM" due to a threshold condition being met.

SNS acts as a highly scalable messaging service that allows you to fan out messages to a large number of subscribers, including email addresses, mobile phone numbers, HTTP endpoints, or even other AWS services. This feature makes SNS particularly useful for alerting, as it can deliver notifications in near real-time to multiple recipients or endpoints based on the alarm's status.

This integration between CloudWatch and SNS ensures that stakeholders can quickly be informed of any operational issues or changes, enabling swift actions to rectify any problems. The other services mentioned do not offer this specific functionality for alerting in response to CloudWatch alarms. SQS facilitates message queuing, AWS Lambda executes code in response to triggers like events and data changes, and Amazon Chime is primarily for communication and meetings rather than alerting based on monitoring conditions.