How to design email suppression rules
Keep unsubscribes, complaints and invalid recipients out of the relevant sending workflows.
A suppression rule needs to survive the next import, automation and platform migration. Treat it as part of audience selection, with a reason and an owner.
Store the reason and scope
| Event | Record | Check |
|---|---|---|
| Subscription unsubscribe | List, recipient, timestamp and source | Every path sending that subscription |
| Spam complaint | Recipient where available, message and stream | The ESP's complaint suppression behaviour |
| Invalid recipient | Full response and classification | Removal from future attempted sends |
| Temporary failure | Response, attempts and queue status | Retry and expiration handling |
Trace every sending path
List campaigns, scheduled automations, application-triggered mail and manual imports. For each, identify where eligibility is checked. A dashboard exclusion is not sufficient if another integration queues the message without reading that exclusion.
Use test contacts you control to exercise the actual path: subscribe, schedule, unsubscribe and confirm that the relevant message is no longer eligible. Test queued messages as well as newly selected audiences.
Keep message purposes explicit
Record whether an unsubscribe concerns one list or all marketing. Handle necessary account messages according to their purpose, rather than relabelling promotional mail as transactional to bypass an opt-out.
Preserve state during imports
Export suppression reasons and dates before a migration. Map them to the destination system and reconcile sample records before sending. Never assume a fresh CSV upload should set everybody back to subscribed.
For any resubscription workflow, keep the new subscriber action and its date. An administrator changing a status field is not the same evidence as a recipient requesting the subscription again.