How to lower email bounce and complaint rates

Learn how to manage your domains reputation and email deliverability through low bounce and complaint rates.

What are bounces and complaints?

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sending emails to addresses that do not exist, are spelled incorrectly, have full inboxes, or when the email address is outdated and no longer in use.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.

Complaints in email marketing typically arise when recipients do not want to receive emails from the sender and mark emails as spam. Common reasons for complaints include irrelevant content, excessive frequency, or recipients not recalling their subscriptions. 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.

Clean Your Mailing Lists

If you dont have a double-opt-in process, this can lead to bounces, as users that provide their email can give you incorrect information. To avoid this it's recommended to implement the double opt. In addition, if you have lists of emails or want to verify, you can run email through email verification tools like zerobounce.net.

Common options for reducing bounce rate:

Recommended
Delete Email Addresses that are invalid, inactive, or obtained without specific consent to receive emails.

Authenticate Emails

Recommended
Verify the email address provided to you is correct. This usually involves sending a confirmation email to the address provided by your user and having the user click a link to verify the email is valid. This prevents the user from providing an incorrect email or email they do not use/own. 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 Flow

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For best deliverability, 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 emails from you. 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.

Email Validation & Suppressions

If you already have a list of emails and want to validate them, Mailgun and SendGrid provide 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.

If you already sent emails to a list, then your ESP likely has a Suppression List. Usually, any emails you target through OneSignal that are on the Suppression List in your ESP will not be sent and will get marked as unsubscribed in OneSignal.