Sending & delivery events
Suppression list
A list of addresses your platform will never send to again — populated automatically by hard bounces, complaints and unsubscribes to protect your sender reputation.
What a suppression list protects
Mailing an address that bounced, complained or unsubscribed hurts your reputation and, for unsubscribes, can break the law. A suppression list is the safety net that stops any future send to those addresses, no matter which campaign, automation or API call tries.
How addresses get suppressed
- Bounced: the address hard-bounced.
- Complained: the recipient marked your mail as spam.
- Unsubscribed: the recipient opted out.
- Manual: you added it yourself, for example after a deletion request.
One list for everything
The most common gap is running transactional and marketing email in separate tools with separate suppression lists, so an address that complained about a newsletter still gets mailed by the other system. In MailCraft there’s one suppression list per team, shared by transactional email, campaigns and automations, and you can view, add and remove entries in the dashboard or through the API.
Let MailCraft handle the details
Authentication, bounces, complaints and suppression are built in. Start free with 3,000 emails a month, no credit card required.
Start freeRelated terms
Full glossarySending & delivery events
Hard bounce
A permanent delivery failure — the address or domain doesn’t exist. Hard bounces should be suppressed immediately and never retried.
Sending & delivery events
Complaint (FBL / feedback loop)
A signal from a mailbox provider that a recipient marked your email as spam. Feedback loops relay these back to senders so the address can be suppressed.
Email types & metrics
Marketing email
Email sent to promote something — a product update, offer, or newsletter — typically requiring recipient consent and a working unsubscribe mechanism.