Microsoft weights sender reputation via SNDS and JMRP, and rejects unauthenticated bulk mail to consumer Outlook.com addresses.
What inbox placement is#
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.
Why it matters#
Delivery rate (accepted by the server) hides the real problem: mail accepted into the spam folder. Placement is the metric that predicts revenue.
Setting up inbox placement for Outlook and Microsoft 365#
- Create seed accounts at Gmail, Outlook, Yahoo, iCloud, and key B2B gateways.
- Send each campaign to the seed list before the full send.
- Record inbox, spam, promotions, and missing counts per provider.
- Correlate drops with content, sending domain, or list segment changes.
- Fix authentication, reputation, or content issues before scaling.
How Outlook and Microsoft 365 reports results#
Open a delivered test message in Outlook and Microsoft 365 and view the original or headers. Look for Authentication-Results and any provider-specific verdict headers. Use the provider's sender dashboard for aggregate reputation.
Common mistakes#
- Trusting a single seed mailbox per provider; use several with different engagement histories.
- Optimizing for the seed test and not real recipient engagement.
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.
Does Outlook and Microsoft 365 require inbox placement?
Microsoft weights sender reputation via SNDS and JMRP, and rejects unauthenticated bulk mail to consumer Outlook.com addresses. Treat inbox placement as required for any meaningful volume.