SNDS

What it means

Microsoft describes SNDS as giving senders the data they need to understand and improve their reputation at Outlook.com, with detailed data about individual IPs, and says reputation is always the responsibility of the sender. It also notes that the data helps IP owners detect compromised servers, malware and botnets on their networks.

Access is per IP: you sign in with a Microsoft account and request access to the addresses you are responsible for, then pass an authorisation step. A September 2026 notice on the portal says access now expires 10 months after approval or migration, so ownership has to be reattested.

SNDS reports on IP addresses, not domains, and only on traffic to Outlook.com. It complements Google's Postmaster Tools and Yahoo's Sender Hub, which cover their own users.