The closest thing to a window into what Microsoft sees - and how to use it.
What SNDS and JMRP Are
These are two free Microsoft programs for people who send mail to Microsoft's consumer domains (outlook.com, hotmail.com, live.com, msn.com) and to Microsoft 365. Smart Network Data Services (SNDS) shows you data about the sending IPs you register - volume, complaint rates, spam-trap hits and filter results. The Junk Mail Reporting Program (JMRP) is Microsoft's feedback loop: when a recipient marks your mail as junk, you get a copy so you can suppress that address.
Why They Matter
Microsoft is famously opaque about why mail is filtered. SNDS and JMRP are the closest thing to a window into what Microsoft sees. If you send at any volume to Microsoft and you have not enrolled, you are flying blind on exactly the signals that decide your placement.
How to Enroll
Both are registered through Microsoft's SNDS site and the related postmaster pages. You verify control of the sending IP range, then data begins to populate. JMRP requires registering the IPs and a receiving address for the complaint feedback. Enrollment requires that you control the IPs - if you send on a shared ESP pool, the ESP is typically already enrolled and sees this data on your behalf.
Reading the Data
Watch three things in SNDS: your complaint rate (keep it well under 0.3%, ideally under 0.1%), any spam-trap hits (should be zero), and the filter result column (green is good). A rising complaint rate or any trap hit is your early warning to pause and investigate before Microsoft acts.
Frequently Asked Questions
What is Microsoft SNDS?
What is JMRP?
Can I use SNDS on a shared ESP IP?
What complaint rate is acceptable at Microsoft?
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