Email Campaign Suppression Logic

Definition

Campaign suppression logic is the set of rules that automatically removes certain subscribers from a campaign's send list before the email is dispatched. Suppression is not the same as unsubscribing — suppressed subscribers remain on the list but are excluded from specific campaigns to prevent over-sending, reduce complaints and maintain deliverability.

A typical suppression rule might exclude anyone who received another campaign within the last 48 hours, anyone flagged as inactive for over 90 days or anyone on a specific domain suppression list.

Common Suppression Rules

• Recency suppression: Exclude subscribers who received another campaign within a defined time window
• Engagement suppression: Exclude subscribers who have not opened or clicked in a set period
• Domain suppression: Exclude addresses at domains with deliverability issues or policy restrictions
• Compliance suppression: Exclude subscribers who have not reconfirmed consent or are in a grace period
• Channel suppression: Exclude subscribers currently engaged in a different campaign flow

Best Practices

• Define suppression rules at the automation level so they are applied consistently rather than manually per campaign
• Review suppression logic quarterly to ensure rules still align with engagement data and business goals
• Distinguish between temporary suppression for campaign pacing and permanent suppression for compliance
• Monitor how many subscribers are being suppressed and why — rising suppression rates may signal a list health problem