Suppression list

A suppression list is checked before every send so certain addresses are never mailed, even if they reappear in a new import. Typical entries: people who unsubscribed or asked not to be contacted, people who marked mail as spam, hard-bounced addresses, and whole domains such as existing customers, partners or companies that asked you to stop.

The rules behind it come from several places. Under GDPR Article 21, once someone objects to direct marketing their data must no longer be processed for that purpose; keeping a minimal record of the objection is how organisations honour it. CAN-SPAM requires honouring opt-outs within 10 business days, and Yahoo's sender best practices ask senders to honour unsubscribes within 2 days. This is general information, not legal advice.

In outbound teams the same person often appears in several reps' lists, tools and sequences. Without a shared suppression list, someone who opted out gets emailed again from a different tool, which produces complaints and possible legal exposure. Make the list team-wide and check it before every campaign and every import.

Skrap.ai has a do-not-contact list of emails and domains in Lists, shared across your team, so everyone works from the same record. Pair it with verification: the free email verifier catches addresses that would hard bounce so you can suppress them before sending. See GDPR and data protection.