AI-powered deliverability scoring: we built an internal tool and here's what we learned
Instead of waiting for deliverability problems to surface, we built an internal ML model to predict inbox placement before hitting send.
The model
We trained on 18 months of sending data — subject lines, content features, send volumes, historical engagement, and recipient domains — mapped to actual inbox placement rates.
Features that predicted deliverability
- Sender reputation score (35% weight): Domain and IP reputation from Postmaster Tools
- Engagement recency (25%): How recently recipients opened or clicked
- Content signals (20%): Link density, image ratio, spam-trigger phrases
- Volume patterns (15%): Consistency with historical sending volume
- Authentication health (5%): SPF/DKIM/DMARC pass rates
Results
The model predicts inbox placement within 5% accuracy for 80% of campaigns. It flagged 3 campaigns in the last quarter that would have had deliverability issues — we adjusted before sending and avoided reputation damage.