Suppression Groups

Suppression groups are admin-managed exclusion lists that let you prevent specific sets of email addresses from receiving certain campaigns. Unlike email topics (which are subscriber-managed), suppression groups are controlled entirely by your team.

Use Cases

Group	Purpose
Competitors	Never email competitor domains
VIP Do Not Disturb	Exclude VIP contacts from mass campaigns
Previous Complainers	Extra caution -- skip contacts who've complained before
Internal Team	Exclude your own team from marketing campaigns
Pending Legal Review	Temporarily exclude contacts under legal review

Managing Suppression Groups

Creating a Group

1. Go to Suppression Groups in the sidebar (under Customers)
2. Click Create Group
3. Fill in:
   • Name -- a descriptive name for the group
   • Description -- optional explanation of the group's purpose
   • Apply to all campaigns by default -- if checked, emails in this group are excluded from every campaign automatically
4. Click Create

Default Groups

When you mark a group as default, its members are automatically excluded from all campaigns without any additional configuration. This is useful for groups like "Competitors" that should always be excluded.

Non-default groups must be explicitly attached to a campaign to take effect.

Adding Members

1. Click a group name or the members icon to open the members panel
2. Enter email addresses (one per line, or comma-separated)
3. Click Add Emails

You can add up to 10,000 emails per request.

Removing Members

Click the X icon next to any member to remove them from the group.

Deleting a Group

Click the trash icon next to a group to permanently delete it. This removes the group definition but does not affect the contacts themselves.

Using Groups in Campaigns

When creating or editing a campaign, you can attach suppression groups in the campaign settings. The Suppression Groups field lets you select one or more groups. During send:

1. Members of explicitly selected groups are excluded from the campaign
2. Members of default groups are always excluded, regardless of campaign settings
3. Suppression group filtering runs after global suppression and topic filtering

How It Works Internally

Suppression group membership is stored in ClickHouse for fast filtering during campaign materialisation. When a campaign is launched:

The order ensures that all filtering layers work together seamlessly.

Best Practices

• Use default groups sparingly -- they affect every campaign, so only use them for truly universal exclusions
• Keep group purposes clear -- use descriptive names and descriptions so your team understands each group's intent
• Review membership regularly -- contacts may need to be added or removed as situations change
• Prefer groups over manual exclusion -- instead of remembering to exclude certain contacts each time, set up a group once