[GTM glossary](/glossary.md) Suppression list Data & Enrichment # Suppression list Also known as: email suppression list, exclusion list In short A suppression list is a list of email addresses, contacts, or accounts that are excluded from outreach, email campaigns, or ad targeting. People appear on it because they opted out, bounced, complained, are existing customers, or are otherwise off limits. Unlike a one-time campaign exclusion, a suppression list is a standing rule applied to every send. Sending to a suppressed address can break the law, damage sender reputation, or annoy a customer who is mid-renewal. This is general information, not legal advice. ## Who belongs on a suppression list * **Opt-outs and unsubscribes:** People who asked to stop hearing from you. Honor these across all tools. * **Hard bounces:** Invalid addresses. Repeated sends hurt deliverability. * **Spam complainers:** Contacts who marked a message as spam. * **Current customers and open deals:** People you do not want in cold outreach or acquisition ads. * **Competitors, partners, and employees:** Contacts where outreach is pointless or awkward. * **Legal or regional exclusions:** Contacts you must not contact for compliance reasons. --- ## Suppression list vs. do not contact list The terms overlap. A do not contact list usually means people who explicitly asked not to be contacted. A suppression list is broader and also includes operational exclusions such as customers and bounced addresses. --- ## How to manage one ### Keep it central Store the master list where every sending tool can read it, or sync it automatically. Separate lists in the email tool, the sequencing tool, and the ad platform will drift apart. ### Check before every send Enroll contacts in a sequence only after matching them against the list. Match on email and on domain for account-level exclusions. ### Update in near real time Unsubscribes should apply immediately. Say a contact opts out of a newsletter on Monday: a sales sequence started on Tuesday must still skip them. --- ## Common mistakes * **Deleting opted-out contacts:** If you delete the record, a later import can re-add them. Keep the address flagged instead. * **Tool silos:** An opt-out in one system never reaches the others. * **No customer exclusion:** Reps cold-email current customers because nothing blocks it. --- ## Suppression list FAQs **What is a suppression list?** A suppression list is a standing list of contacts or accounts that must be excluded from emails, outreach sequences, and ad audiences. It includes opt-outs, bounced addresses, spam complainers, and often current customers, and is checked before every send. **What is the difference between a suppression list and an unsubscribe list?** An unsubscribe list holds people who chose to opt out of your messages. A suppression list is broader: it includes those people plus hard bounces, spam complaints, customers, and other contacts you have decided not to reach for operational or legal reasons. **Why is a suppression list important for email deliverability?** Sending to invalid addresses or people who complained raises bounce and spam rates, which mailbox providers use to judge your sender reputation. A suppression list prevents repeat sends to those addresses, protecting inbox placement for everyone else. **Should you delete contacts who unsubscribe?** Usually no. Deleting the record can let the same address be re-imported later and emailed again. Keep the contact and mark it as suppressed so the opt-out is remembered. Specific erasure requests follow privacy rules, so check with counsel. Share term --- ## More related phrases * [CAN-SPAM](/glossary/can-spam.md) * [CASL](/glossary/casl.md) * [CCPA](/glossary/ccpa.md) ## Similar phrases * [Do not contact list](/glossary/do-not-contact-list.md) A do not contact list records the people, domains, and companies your team must not message or call, so outreach respects opt-outs, legal limits, and business rules. * [Opt-out](/glossary/opt-out.md) An opt-out is a person's request to stop receiving marketing or sales messages, or to stop having their data used, and teams must record and honor it across every system. * [Email validation](/glossary/email-validation.md) Email validation checks whether an email address is correctly formatted and technically able to exist, catching typos and invalid domains before they reach your CRM or sending tool. * [GDPR compliance](/glossary/gdpr-compliance.md) GDPR compliance means meeting the requirements of the EU General Data Protection Regulation when collecting, using, and storing personal data of people in the European Union. * [Data privacy](/glossary/data-privacy.md) Data privacy is the set of rules and practices that govern how personal information is collected, used, stored, and shared, so people keep control over their data.