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Amazon Simple Email Service
Developer Guide (API Version 2010-12-01)

Amazon SES Bounce FAQ

Q1. Why do you care about my bounces?

High bounce rates are often used by entities such as ISPs, mailbox providers, and anti-spam organizations as indicators that senders are engaging in low-quality email-sending practices and their email should be blocked or sent to the spam folder.

Q2. What should I do if I receive a probation or suspension notice for my bounce rate?

Fix the underlying problem and appeal to get your case reevaluated. For information about the appeal process, see the FAQs on probation and suspension. In your appeal, in addition to the information requested in the probation and suspension FAQs, tell us the following:

  • The method you use to track your bounces

  • How you ensure that the email addresses of new recipients are valid prior to sending to them. For example, which of the recommendations are you following in Q11. What can I do to minimize bounces?

Q3. What types of bounces count toward my bounce rate?

Your bounce rate includes only hard bounces to domains you have not verified. Hard bounces are permanent delivery failures such as "address does not exist." Temporary and intermittent failures such as "mailbox full," or bounces due to blocked IP addresses, do not count toward your bounce rate.

Q4. Do you disclose the Amazon SES bounce rate limits that trigger probation and suspension?

No, but you can find general bounce rate guidelines and tips on how to avoid bounces in the Amazon Simple Email Service Email Sending Best Practices whitepaper.

Q5. Over what period of time is my bounce rate calculated?

We don't calculate your bounce rate based on a fixed period of time, because different senders send at different rates. Instead, we look at what is called a representative volume, which represents a reasonable amount of mail with which to evaluate your sending practices. To be fair to both high-volume and small-volume senders, the representative volume is different for each user and changes as the user's sending patterns change.

Q6. Can I calculate my own bounce rate by using the information from the Amazon SES console or the GetSendStatistics API?

No. The bounce rate is calculated using representative volume (see Q5. Over what period of time is my bounce rate calculated?). Depending on your sending rate, your bounce rate can stretch farther back in time than the Amazon SES console or GetSendStatistics can retrieve. In addition, only emails to non-verified domains are considered when calculating your bounce rate. However, if you regularly monitor your bounce rates using those methods, you should still have a good indicator that you can use to catch problems before they get to levels that trigger a probation or suspension.

Q7. How can I find out which email addresses bounced?

Examine the bounce notifications that Amazon SES sends you. The email address to which Amazon SES forwards the notifications depends on how you sent the original messages, as described at Amazon SES Notifications Through Email. You can also set up bounce notifications through Amazon Simple Notification Service (Amazon SNS), as described at Monitoring Using Amazon SES Notifications. Note that simply removing bounced addresses from your list without any additional investigation might not solve the underlying problem. For information about what you can do to reduce bounces, see Q11. What can I do to minimize bounces?.

Q8. If I haven't been monitoring my bounces, can you give me a list of addresses that have bounced?

No. We cannot give you a comprehensive list. You should be regularly monitoring your bounces by email or through Amazon SNS.

Q9. How should I handle bounces?

You need to remove bounced addresses from your mailing list and stop sending mail to them immediately. If you are a small sender, it might be sufficient to simply monitor bounces through email and manually remove bounced addresses from your mailing list. If your volume is higher, you will probably want to set up automation for this process, either by programmatically processing the mailbox where you receive bounces, or by setting up bounce notifications through Amazon SNS. For more information, see Monitoring Using Amazon SES Notifications.

Q10. Could my emails be bouncing because I've reached my sending limits?

No. Bounces have nothing to do with sending limits. If you try to exceed your sending limits, you will receive an error from the Amazon SES API or SMTP interface when you try to send an email.

Q11. What can I do to minimize bounces?

First, be sure that you are aware of your bounces (see Q7. How can I find out which email addresses bounced?). Then follow these guidelines:

  • Do not buy, rent, or share email addresses. Use only addresses that specifically requested your mail.

  • Remove bounced email addresses from your list.

  • When you ask for email addresses, ask twice and require a match to minimize typos.

  • Use double opt-in to sign up new users. That is, when a new users sign up, send them a confirmation email that they need to click before receiving any additional mail. This prevents people from signing up other people as well as accidental signups.

  • If you must send to addresses that you haven't mailed lately (and thus you can't be confident that the addresses are still valid), do so only with a small portion of your overall sending. For more information, see our blog post Never send to old addresses, but what if you have to?.

  • Ensure that you are not structuring signups to encourage people to use fictional addresses. Either do not provide any value to new users until their email address is verified, or ask for their address only when they specifically sign up to receive mail.

  • If you have an "email a friend" feature, be sure you use CAPTCHA or a similar mechanism to discourage automated use of the feature, and do not allow arbitrary content to be inserted by the user. For more information about CAPTCHA, see http://www.captcha.net/.

  • If you are using Amazon SES for system notifications, ensure that you are sending the notifications to real addresses that can receive mail. Also consider turning off notifications that you do not need.

  • If you are testing a new system, be sure you are either sending to real addresses that can receive email, or you are using the Amazon SES mailbox simulator. For more information, see Testing Amazon SES Email Sending.