Without structure, shared inboxes leak customers. With it, they become a measurable team workflow.
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#
- Assign an owner to every incoming thread automatically or by rule.
- Track status: open, waiting, resolved.
- Set response-time targets and alert on breaches.
- Draft replies with AI using the team's past answers as style reference.
Frequently asked questions#
Should we use a shared mailbox or a helpdesk?
Under a few hundred messages a week, a well-managed shared inbox works. Beyond that, ticketing adds needed structure.