Suppressions, bounces and unsubscribes

A suppression list is not a punishment list. It is the system's memory of who should not receive mail, so that a decision made once is not undone by the next campaign.

Every entry has a reason, and the reasons are not interchangeable.

Who this is for

Anyone sending campaigns, and admins responsible for compliance.

Before you start

• Permission to manage email suppressions.
• Nothing else — suppressions accumulate on their own as you send.

The four reasons
Unsubscribed means the person asked to stop, and that must be honoured. Bounced means delivery failed — often because the address does not exist. Complained means they marked your mail as spam, which is the most serious signal and the one that damages your sending reputation most. Manual means someone added the address deliberately.

Work with the suppression list

1. Let it fill itself
   Unsubscribes, bounces and complaints are recorded as they happen. You do not have to maintain the list by hand for it to work.
2. Read the reasons, not just the count
   A growing list of unsubscribes and a growing list of complaints mean very different things. Complaints are the ones to act on urgently.
3. Add addresses manually when you need to
   The manual reason exists for the cases the system cannot know about — someone who asked you to stop by phone, or an address you know is a trap.
4. Never route around a suppression
   Re-importing a list to get around an unsubscribe is both a compliance problem and a reliable way to generate complaints, which is worse for you than the lost recipient.
5. Investigate a spike
   A sudden jump in complaints usually points at one send — the wrong audience, or a message that did not look like what people signed up for. Find that send rather than treating it as background noise.

The four suppression reasons

What you get

• Unsubscribe requests honoured automatically on later sends.
• Dead addresses removed from your sending, protecting your reputation.
• A reason on every entry, so the list is diagnosable rather than just long.
• A manual route for the cases only a human knows about.

Frequently asked questions

Can I remove someone from the suppression list?

Treat this with care. If someone unsubscribed, removing them so you can mail again is exactly the behaviour that generates spam complaints. A genuine re-subscription request from the person is a different matter from you deciding on their behalf.

What is the difference between a bounce and a complaint?

A bounce means delivery failed, often because the address does not exist. A complaint means it was delivered and the person marked it as spam. Complaints do far more damage to your sending reputation.

Does a suppression stop one-to-one email too?

The suppression list governs sending to that address. If someone has asked not to be contacted, that is the intent to respect regardless of the channel.

Why would I add a suppression manually?

For anything the system cannot observe — someone who asked you to stop in a phone call, or an address you have reason not to mail.