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Account-based suppression

Suppression is a critical mechanism to ensure that emails are not sent to recipients who have opted out, bounced, reported spam, or otherwise should no longer be contacted.

MX18 automatically tracks and stores suppression records for your account — helping you maintain compliance, improve deliverability, and avoid user complaints.

What is suppression?

A suppression list is a set of email addresses that are blocked from receiving messages.

MX18 suppresses recipients based on:

  • Hard bounces
  • Spam complaints
  • Unsubscribes
  • Manual uploads by your team

These addresses are automatically checked each time you attempt to send an email.

If the recipient matches your suppression list, the message will trigger a dropped event — meaning it won’t be sent or counted toward billing.

See Events Tracking to learn more about the dropped event.

Account-level suppression

MX18 maintains your suppression list at the account level.

This means:

  • It is unique to your account and not shared across other domains
  • Every send request checks against this list before attempting delivery
  • Helps protect your sender reputation from accidental sends to bad contacts

Manage suppression via dashboard

You can manage suppressed contacts directly in the MX18 Web App:

  1. Go to app.mx18.com
  2. Navigate to Settings > Suppression Management
  3. View, search, or delete suppressed contacts
  4. Click Upload to import suppression lists from past providers (CSV format supported)

We highly recommend uploading historical suppression data when migrating from another ESP — this prevents re-sending to unsubscribed or invalid users and protects your reputation.

Need help?

Need help formatting your suppression list or understanding suppression logic?

  • Reach out to support@mx18.com
  • We can help you validate and bulk-import suppression records