Generate CloudWatch alarm JSON for metrics with thresholds and actions.
Last verified: May 2026
Output will appear here...The CloudWatch Alarm Builder helps you configure CloudWatch alarm definitions through a guided form interface. You can select metrics, set thresholds, configure evaluation periods, and define alarm actions like SNS notifications or Auto Scaling policies. The tool generates the complete alarm configuration as JSON or CLI commands that you can use with CloudFormation, Terraform, or the AWS CLI, eliminating the need to memorize metric namespaces and statistic options.
Your team's pager goes off 30+ times/week with CloudWatch alarms — most are false positives from a single noisy minute on the API latency p99 metric. You rebuild the alarm with this tool: same threshold (500ms), but evaluation periods = 5 with datapoints to alarm = 4. Pager volume drops from 30/week to 4/week, and the 4 are real incidents that stay above 500ms for 4+ minutes. Engineer happiness improves measurably.
M out of N evaluation periods (e.g., 3 of 5) is your most powerful tool against alert noise. A 3-of-5 pattern at 1-minute periods catches issues that persist 3 minutes within a 5-minute window — much better than 1-of-1 which fires on a single anomalous minute. Almost every CloudWatch alarm should use this pattern.
Composite alarms (combining multiple alarms with AND/OR logic) are dramatically underused. Instead of paging on 'CPU > 80%' which constantly false-alarms, page on 'CPU > 80% AND error rate > 1%' — much higher signal-to-noise. Composite alarms are free; you only pay for the underlying metric alarms.
Alarm 'INSUFFICIENT_DATA' state is treated as separate from OK and ALARM by SNS subscriptions. If you forget to handle INSUFFICIENT_DATA in your runbook, alarms with intermittent metric publishing (e.g., custom metrics from low-traffic Lambdas) will silently fail to alert. Always set TreatMissingData explicitly: 'breaching', 'notBreaching', or 'ignore'.
The builder constructs a CloudWatch alarm definition with metric namespace, metric name, dimensions, statistic, period, evaluation periods, datapoints to alarm, threshold, comparison operator, and actions (SNS topic ARN, Auto Scaling action). Output is generated in three formats: aws cloudwatch put-metric-alarm CLI command, AWS::CloudWatch::Alarm CloudFormation, and aws_cloudwatch_metric_alarm Terraform.
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