Suppression list
A list of addresses that must never be mailed again (unsubscribes, complainants, hard bounces), checked before every send whatever list the address appears on.
What it means
A suppression list outranks every other list: an address on it is skipped even if it is imported again from another source. Amazon SES, for example, keeps an account-level suppression list to which it adds addresses that hard bounce or complain, and does not send to them.
Providers and regulators expect one. Apple asks bulk senders not to reactivate addresses already on their unsubscribe or suppression list. The UK's ICO calls it good practice to keep a do-not-email list of businesses that object and to screen new marketing lists against it. CAN-SPAM forbids selling or transferring the addresses of people who opted out.
Keep suppression shared across tools and brands, so an unsubscribe in one system stops mail from all of them.
Related terms
On this site
Sources
What this definition rests on. The wording is ours; the facts are theirs.
- Amazon SES: Account-level suppression listdocs.aws.amazon.com
- Apple Support: Postmaster information for iCloud Mailsupport.apple.com
- ICO: Electronic mail marketing (guide to PECR)ico.org.uk
- FTC: CAN-SPAM Act, a compliance guide for businessftc.gov
All 432 terms in the glossaryThe wiki: blocklists and bounce codes