Why It Matters
Deliverability and inbox placement are different things, and the distinction matters. A 99% delivery rate sounds great, but if 30% of those "delivered" emails land in spam, you've got a serious problem. Your open rates depend directly on inbox placement. An email in the spam folder might as well not exist — fewer than 1% of recipients check their spam folder regularly.
How It Works
After your email is accepted by the receiving server (that's deliverability), the server's filtering algorithms decide where to put it. Gmail uses hundreds of signals including your sender reputation, authentication results, content analysis, and — most heavily — how that specific recipient has interacted with your past emails. Someone who always opens your emails will see them in their primary inbox. Someone who ignores them might see them in promotions or spam.
Quick Tips
- Use seed testing tools to check inbox placement before sending to your full list — they'll show you where your email lands across different providers
- Focus on engagement over everything else; consistently high open and click rates are the strongest signal for primary inbox placement
- If you're landing in Gmail's Promotions tab, ask engaged subscribers to drag your email to Primary — Gmail learns from that action