Inbox placement is the percentage of sent mail that lands in the primary inbox rather than spam, promotions, or being blocked. It is measured with seed lists across major providers and panel data from real mailboxes.
What good looks like#
- Done: Create seed accounts at Gmail, Outlook, Yahoo, iCloud, and key B2B gateways.
- Done: Send each campaign to the seed list before the full send.
- Done: Record inbox, spam, promotions, and missing counts per provider.
- Done: Correlate drops with content, sending domain, or list segment changes.
- Done: Fix authentication, reputation, or content issues before scaling.
What bad looks like#
- Seen in audits: Trusting a single seed mailbox per provider; use several with different engagement histories.
- Seen in audits: Optimizing for the seed test and not real recipient engagement.
How to move from bad to good#
Work through the good list in order and re-verify after each change. Most teams find one or two items from the bad list already present; fixing those usually produces the largest improvement.
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.