GDPR and similar laws require minimization and timely response to requests; over-retention increases breach exposure.
The metrics that matter#
- Authentication pass rate: share of mail passing SPF, DKIM, and DMARC alignment. Healthy: 99% or higher.
- Spam complaint rate: Gmail enforces at 0.3%; stay under 0.1%.
- Hard bounce rate: under 2%; above 5% triggers platform reviews.
- Inbox placement: above 90% across major providers via seed tests.
- Engagement: click and reply rates by segment; opens are unreliable after Mail Privacy Protection.
Where to read them#
- Google Postmaster Tools for Gmail domain reputation, spam rate, and authentication.
- Microsoft SNDS and JMRP for Outlook.com IP reputation and complaints.
- Your ESP's delivery and bounce reports.
- DMARC aggregate reports for authentication by source.
Improving the numbers#
- Classify data: consent records, engagement logs, message content.
- Set retention periods per class and automate deletion.
- Build a DSAR process that can search and export across ESP, CRM, and mailbox.
- Log every deletion and export for accountability.
Frequently asked questions#
How long can I keep unsubscribed contacts?
Keep the suppression record indefinitely (email only) so you never re-mail them; delete profile data per your retention schedule.