How to Lower Email Bounce and Complaint Rates

Prevent deliverability issues by lowering complaints and bounces on your emails.

What are bounces?

A bounce generally occurs when sending emails to addresses that do not exist, are spelled incorrectly, have full inboxes, or when the email address is outdated and no longer in use. Bounces can also result from blockage by domains with a poor sender reputation (due to too many spam complaints), if specific content in your message is flagged, or if there's a restrictive DMARC record for your sending domain. It is recommended to keep your "Bounce Rate" as low as possible, as it can become a problem if it gets too high and may lead to a disabled domain.

What are complaints?

Complaints or reported spam in email marketing arise when recipients do not want to receive emails from the sender and mark or report emails as spam. Common reasons for complaints include irrelevant content, excessive frequency, or emailing recipients that did not opt-in. To maintain a positive sender reputation and avoid deliverability issues, it is important to minimize complaint rates. Regularly analyze feedback, adjust content strategies, and provide easy opt-out options to ensure a satisfactory email experience for recipients.

A high complaint rate or bounce rate can cause you to violate our Acceptable Use Policy.

Remove Unengaged Recipients

Recommended for complaints and bounces
Consider implementing a sunset policy for recipients that do not engage with your emails after a set amount of time. Unengaged recipients are more likely to complain on subsequent emails and are more likely to become invalid. Try excluding recipients who have not engaged with 4 emails in a row or have not engaged with emails in 3 months, whichever comes first. This can always be adjusted later.

In Journeys, this can be done with Yes/No Branches by only allowing recipients to continue through a Journey if they have opened or clicked a prior email. You can also Tag unengaged users in Journeys so that they can be excluded in your other Segments.

Implement a Confirmed or Double Opt-in

Recommended for complaints and bounces
Send a confirmation email to the address provided by your user and have the user click a link in the confirmation email to verify that their address is valid and that they want to receive future emails. This prevents the user from providing an incorrect email or email they do not use/own. This also ensures that you collect recipients who truly want your emails. Once validated, it is then best to pass it to OneSignal. This is also known as double opt-in and will help reduce bounces and complaints.

Email Consent

Recommended for complaints
You should only send emails to recipients who have knowingly signed up to receive emails. When a person uses a valid email to sign in to the app, they don't necessarily acknowledge that they want to receive emails. Make sure to ask the user to acknowledge that they will be receiving marketing or promotional emails. If you use a prompt asking the customer what kind of emails they want, you can then set Data Tags on the user, marking what kind to send.

Clean Your Segments

Recommended for bounces
Delete Email Addresses that are invalid, inactive, or obtained without specific consent to receive emails. Look for email addresses that are obviously invalid, ie [email protected], [email protected], [email protected]

If you already sent emails from another email platform, then that platform likely has a Suppression List. These can be uploaded to OneSignal with a User Data Tag like "do_not_send", which can be used to exclude them from your Segments.

Use Targeted Segments

Recommended for complaints
Try to avoid "One Size Fits All" emails. Create a Preference Center and rely on Data Tags to make segments. This will help you create templates and journeys that are more relevant and expected to various segments.

Use Retargeting Messages for follow up emails to ensure they go to those who were engaged with the previous email.

Email Validation Tools

Note: List validation and verification tools do not reduce complaints and do not catch all invalid email addresses. It is strongly recommended that these tools are used alongside best practices. There are Email Validation tools that you can use to check a list before uploading to OneSignal. See:

Once you have a validated list, you can import emails following the Import Email Addresses guide.