Delivery rate (accepted by the server) hides the real problem: mail accepted into the spam folder. Placement is the metric that predicts revenue.
Mistake 1: Trusting a single seed mailbox per provider; use several with different engagement histories#
Why it hurts: this undermines inbox placement at the point where mailbox providers make their decision, and it is rarely surfaced by your own tooling until placement drops.
Fix: Create seed accounts at Gmail, Outlook, Yahoo, iCloud, and key B2B gateways.
Mistake 2: Optimizing for the seed test and not real recipient engagement#
Why it hurts: this undermines inbox placement at the point where mailbox providers make their decision, and it is rarely surfaced by your own tooling until placement drops.
Fix: Send each campaign to the seed list before the full send.
Frequently asked questions#
Why does mail land in Gmail Promotions?
Gmail classifies by content and sender behavior. Promotions is not spam and often performs well; do not over-optimize to escape it.
What is a good inbox placement rate?
Above 90% is healthy. Below 80% indicates a reputation or authentication problem.