Suppression lists prevent sending to addresses that bounced, unsubscribed, or complained. Learn why suppression is essential for reputation and legal compliance.
A suppression list is a list of email addresses you should not send to, typically because they unsubscribed, hard bounced, or marked your messages as spam. Suppression protects deliverability and reduces compliance risk.
Most email systems automatically suppress hard bounces and unsubscribes, but teams sometimes manage additional suppression sources, such as internal do-not-contact lists, role accounts, or legal exclusions.
Keeping suppression accurate is critical. Accidentally resending to unsubscribed or complaining recipients increases spam complaints and can trigger blocks. A reliable suppression workflow is one of the highest ROI deliverability practices.