Suppression List
A suppression list is a database of email addresses that have been excluded from future email sends. Addresses are added when they unsubscribe, hard bounce, or report your email as spam. Suppression lists protect sender reputation by preventing emails to addresses that have explicitly or implicitly opted out.
Why Suppression Lists Matter
Sending to suppressed addresses directly damages your reputation:
- ●Unsubscribed addresses - Resending violates CAN-SPAM and GDPR
- ●Hard bounced addresses - Resending increases bounce rates and signals poor list management
- ●Complained addresses - Resending to spam reporters is the fastest way to get blocklisted
Email platforms manage suppression lists automatically. Never manually remove addresses from your suppression list without a confirmed re-opt-in.
Related Terms
List Hygiene
The practice of maintaining a clean email list by removing invalid and inactive addresses.
Complaint Rate
The percentage of recipients who mark your email as spam, a critical reputation metric.
CAN-SPAM Act
US law setting rules for commercial email, including opt-out requirements and header accuracy.
Need help with email deliverability?
Transmit handles authentication, warmup, and reputation isolation automatically.