Amazon Simple Email Service (SES) is one of the cheapest email delivery providers for sending bulk emails. With prices as low as $10 for 100,000 emails, compared to $135 per month with Mailchimp or $35 per month with SendGrid, the savings are substantial. However, this comes with a significant caveat: ambiguous email complaint rules.

Amazon SES Increasing Complain Rate

The problem lies in Amazon SES’s approach to calculating email complaint rates. Unlike some email service providers that reset email complaint rates percentage after a certain period, Amazon SES’s complaint rate appears to be historical. This means that once the rate increases, it becomes increasingly difficult to bring it back down, regardless of changes made to email practices or content. The formula Amazon SES uses to calculate the complaint rate is not publicly disclosed, and even their support team often lacks clear guidance on how to address this issue.

For instance, I was using Amazon SES for sending registration confirmation emails. Surprisingly, some users marked these emails as spam instead of confirming. This led to an increase in the complaint rate, forcing us to temporarily disable email confirmation to avoid further problems.

Amazon SES Account Review

If your complaint rate exceeds 0.5%, your SES account could be suspended or placed under review. This makes Amazon SES a risky choice if you plan to use it for sending cold emails or if you anticipate that your emails may be marked as spam by recipients. While the cost savings are tempting, the potential for account suspension due to high complaint rates is something you should be prepared for.

This issue has been raised by some SES users as a bug, but there has not been any helpful response from AWS.