Glossary · Compliance · Last updated October 31, 2026
Suppression list
A suppression list is a list of addresses or domains you must never email again, such as opt-outs, hard bounces and complaints, checked before every send.
Also called: Do-not-contact list, Do-not-email list, Blocklist (sender side).
A suppression list protects two things: the law and your reputation. CAN-SPAM requires honoring opt-outs within 10 business days; CASL requires unsubscribes to take effect within 10 business days; Yahoo asks bulk senders to honor unsubscribes within 2 days. Hard bounces and spam complaints belong on the list too, because sending to them again damages your sender reputation.
The list only works if it's applied everywhere. A common failure is suppressing an address in one campaign or one tool while it stays live in another, or rebuilding a list from scratch and re-importing everyone who opted out last quarter.
Agencies have an extra problem: one business may be a prospect for several clients. Agree in writing who owns opt-outs, and decide whether an opt-out from one client's campaign suppresses that business for every client. For local markets, where you'll email the same towns again, a shared list saves real trouble.
Suppress at the domain level when a business asks not to be contacted at all, not just the single address that replied.
Example
A plumber replies "remove me." The agency adds the address and the domain joesplumbing.com to its shared suppression list, so next quarter's rebuilt Austin list skips the business automatically.
In Leadraft
Your do-not-contact list is applied to every export and push automatically, and Instantly bounce feedback flows back from pushed leads.
Sources
Related terms
- CAN-SPAM ActThe CAN-SPAM Act is the US law for commercial email; it allows cold email without consent but requires honest headers, an address and a working opt-out.
- Hard bounceA hard bounce is a permanent delivery failure, such as an address that doesn't exist, returned with an SMTP reply code starting with 5.
- CASLCASL is Canada's Anti-Spam Legislation, which requires consent before most commercial emails, including implied consent for published business addresses.
- Sender reputationSender reputation is the trust mailbox providers place in your sending domain and IP, built from complaints, bounces, authentication and engagement.
- DeduplicationDeduplication is finding and merging records that describe the same business or person, so each appears once in a list.
Further reading
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