Which service is best suited for monitoring user activity within an AWS account?

The best service for monitoring user activity within an AWS account is AWS CloudTrail. This service is specifically designed to capture and log all API calls made in your AWS account, which includes activities performed by users, AWS services, and other accounts. CloudTrail records the who, what, when, and where of AWS account activity, providing a comprehensive view of user actions across AWS resources.

By enabling CloudTrail, you can gain insights into user behavior, troubleshoot operational issues, and maintain compliance for regulatory requirements. The logs generated by CloudTrail can be analyzed for security monitoring, audits, and accountability, making it an essential tool for tracking user actions and understanding patterns of use within the AWS environment.

Other services, while important for various aspects of AWS management, do not focus directly on user activity monitoring in the same way. AWS Config is primarily used for resource configuration tracking and compliance auditing, Amazon EventBridge serves as an event bus for integrating applications and routing events rather than logging user actions, and CloudWatch Alarms are used for monitoring system performance and resource utilization rather than tracking user interactions specifically.