What sender reputation is#
Sender reputation is the score mailbox providers assign to a sending domain and IP based on complaint rates, bounce rates, engagement, spam-trap hits, and authentication history. It determines whether mail is delivered, filtered, or rejected.
Why it matters#
Reputation is the dominant factor in inbox placement. Content matters far less than the trust a provider has in your domain.
How mailbox providers use it#
Gmail, Microsoft, and Yahoo combine authentication results, sender reputation, and recipient engagement into a placement decision made per message. Sender reputation feeds directly into that model, and weaknesses compound with other signals.
How to measure the impact#
- Baseline inbox placement with seed tests before any change.
- Make one change at a time and hold volume steady.
- Re-test after 48 to 72 hours; provider models need time to update.
- Track Postmaster Tools and SNDS alongside your seed results.
Improving it#
- Register in Google Postmaster Tools and Microsoft SNDS to see your domain and IP reputation directly.
- Keep spam complaints below 0.1% (Gmail's threshold is 0.3% for enforcement) and hard bounces below 2%.
- Segment by engagement and stop sending to contacts inactive for 90+ days.
- Authenticate with SPF, DKIM, and DMARC so reputation accrues to your domain rather than a shared IP.
- Ramp volume gradually after any pause longer than two weeks.
Frequently asked questions#
Domain reputation vs IP reputation: which matters more?
Domain reputation now dominates at Gmail and Yahoo. IP still matters for Microsoft and for dedicated-IP senders.
How long does it take to repair a bad reputation?
Four to eight weeks of clean, low-volume sending to engaged recipients is typical.