Monitoring AWS SES Reputation with CloudWatch Alarm: Recommended Thresholds

1. What is SES Reputation?

AWS SES monitors your sending reputation, which affects email deliverability. Reputation is mainly influenced by:

• Bounce Rate (SES:Reputation.BounceRate) – Too many bounces can lead to account restrictions.
• Complaint Rate (SES:Reputation.ComplaintRate) – Recipients marking your emails as spam will negatively impact your reputation.

A high complaint rate can cause SES to temporarily or permanently restrict your sending ability.

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2. Recommended SES Reputation Thresholds

AWS SES recommends keeping both bounce and complaint rates low.

Metric	Safe Level	Warning Level	Critical Level (SES Restriction Risk)
Bounce Rate (SES:Reputation.BounceRate)	< 1.0%	1.0% – 2.0%	> 2.0% (High Risk 🚨)
Complaint Rate (SES:Reputation.ComplaintRate)	< 0.1%	0.1% – 0.3%	> 0.3% (High Risk 🚨)

Important:

• AWS SES may throttle or suspend your account if your complaint rate exceeds 0.3%.
• Complaint rate issues should be resolved immediately by removing affected recipients and improving email targeting.

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3. Setting Up CloudWatch Alarms for SES Reputation Metrics

SES provides two key metrics in CloudWatch:

• SES:Reputation.BounceRate → Monitors bounce rates
• SES:Reputation.ComplaintRate → Monitors complaint rates

CloudWatch Alarm for Bounce Rate

aws cloudwatch put-metric-alarm \\
  --alarm-name "SES-BounceRate-Alarm" \\
  --metric-name "Reputation.BounceRate" \\
  --namespace "AWS/SES" \\
  --statistic "Average" \\
  --threshold 0.02 \\
  --comparison-operator "GreaterThanOrEqualToThreshold" \\
  --evaluation-periods 1 \\
  --period 3600 \\
  --alarm-actions "arn:aws:sns:your-region:your-account-id:your-topic"

• Triggers an alarm if bounce rate exceeds 2.0% (0.02)

CloudWatch Alarm for Complaint Rate

aws cloudwatch put-metric-alarm \\
  --alarm-name "SES-ComplaintRate-Alarm" \\
  --metric-name "Reputation.ComplaintRate" \\
  --namespace "AWS/SES" \\
  --statistic "Average" \\
  --threshold 0.003 \\
  --comparison-operator "GreaterThanOrEqualToThreshold" \\
  --evaluation-periods 1 \\
  --period 3600 \\
  --alarm-actions "arn:aws:sns:your-region:your-account-id:your-topic"

• Triggers an alarm if complaint rate exceeds 0.3% (0.003)

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4. What to Do If Reputation Metrics Are Too High

(1) If Bounce Rate Is Too High (> 2.0%)

✅ Solution:

• Remove invalid email addresses immediately from your mailing list.
• Use email verification services (e.g., Amazon SES Email Verification, ZeroBounce).
• Enable SNS bounce notifications to monitor failed deliveries.

(2) If Complaint Rate Is Too High (> 0.3%)

✅ Solution:

• Identify and remove users who report your emails as spam.
• Ensure emails only go to users who have explicitly opted in.
• Improve email content quality, making sure it is relevant to recipients.
• Add an easy-to-use “Unsubscribe” link in every email.

(3) Implement SNS Notifications for Automated Handling

To respond quickly to issues, set up SNS notifications for SES reputation events:

1. Create an SNS topic (ses-reputation-alerts).
2. Subscribe your email or Lambda function to receive notifications.
3. Configure AWS SES to send bounce and complaint events to SNS.

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5. Summary: Best Reputation Thresholds for CloudWatch Alarms

Metric	Warning Alert	Critical Alert (High Risk 🚨)
Bounce Rate (SES:Reputation.BounceRate)	1.0% (0.01)	2.0% (0.02)
Complaint Rate (SES:Reputation.ComplaintRate)	0.1% (0.001)	0.3% (0.003)

By implementing these thresholds, you can ensure AWS SES maintains a good reputation and avoid sending restrictions