Suppression List
01 Definition
Suppression List meaning: A list of addresses your system blocks from receiving mail, even if they exist elsewhere.
A suppression list holds addresses that must never be emailed, such as unsubscribes, bounces, complaints, and manual blocks. The sending platform checks it before every send and skips those contacts. Honoring suppression is a legal requirement for opt-outs under most email laws.
Also called
Why it matters
How Suppression List fits the work
Suppression lists prevent you from mailing people who opted out or caused problems, protecting both compliance standing and sender reputation.
In context
When a user unsubscribed, the platform added them to the suppression list, so later campaigns skipped their address automatically.
Practical note
Keep suppression global across your account, not per campaign, and preserve it during platform migrations so previously unsubscribed people are not accidentally re-added.