Microsoft SNDS & JMRP: The Free Tools Every Sender Should Be Using
If you send any meaningful volume to Outlook.com or Hotmail, you should be in SNDS and JMRP. They're free, take 15 minutes to set up, and tell you what Microsoft thinks of your IPs in near real time.
Most senders who struggle with Microsoft deliverability have never enrolled in the two free tools Microsoft built specifically to help them: SNDS and JMRP. If you're one of them, this is the highest-ROI 15 minutes you'll spend on email this quarter.
What SNDS Is
Smart Network Data Services (SNDS) is Microsoft's free dashboard that shows you, per IP, the reputation Outlook.com is assigning to it. You see:
- A color status: green, yellow, or red.
- Complaint rate (per JMRP feedback).
- Trap hits — how often mail from this IP hit a Microsoft spam trap.
- Message volume sampled.
- Filter result percentages — how Outlook.com filtered the sampled mail.
The data refreshes daily and goes back ~30 days.
URL: https://sendersupport.olc.protection.outlook.com/snds/
What JMRP Is
Junk Mail Reporting Program (JMRP) is Microsoft's feedback loop. When an Outlook.com / Hotmail user hits "report junk" on a message from your IP, JMRP sends you the original message so you can suppress that recipient.
It's the closest thing Microsoft offers to Gmail's FBL (which barely exists for non-large-senders). Without JMRP you can't act on complaints — and complaints are the single biggest driver of S3140 blocks.
URL: https://sendersupport.olc.protection.outlook.com/snds/JMRP.aspx
How to Enroll in SNDS
- Visit the SNDS URL above and sign in with any Microsoft account (work, school, or personal).
- Click "Request access".
- Add the IPs (or CIDR ranges) you send from. You can submit up to 100 ranges per request.
- Microsoft sends a verification email to the abuse@ or postmaster@ address on the WHOIS record for each IP block. Whoever owns that mailbox must click the link to authorize access.
- Once verified — usually within an hour — the IPs show up in your dashboard.
If you don't control the abuse@ address (e.g. you're on a shared IP at an ESP), your ESP has SNDS access for that pool. Ask them for the data.
How to Enroll in JMRP
- Visit the JMRP URL above.
- Submit each IP or range you send from, plus the email address that should receive complaint reports (use a dedicated mailbox —
fbl@yourdomainis a common convention). - Same WHOIS verification flow as SNDS.
- Once approved, complaints start arriving as standard ARF-format messages.
Plug that mailbox into your suppression system so any address that lands in JMRP is immediately suppressed from future sends.
Reading the SNDS Data Table
| Column | What it means | Healthy value |
|---|---|---|
| RCPT commands | Recipient attempts sampled | n/a (volume signal) |
| Data commands | Messages actually transmitted | Close to RCPT |
| Trap message period | Days in which traps were hit | "Not applicable" is best |
| Trap hits | Number of trap recipients | 0 ideal, <3 tolerable |
| Sample HELO | What you EHLO'd as | Matches your PTR |
| Sample MAIL FROM | Return-path domain | Matches your sending domain |
| Complaint rate | % of mail Outlook.com users reported | < 0.1% target, > 0.3% danger |
| Filter result | % filtered as spam by Outlook.com | < 1% target |
What the Colors Mean
- Green — Outlook.com is generally trusting your IP. Most mail goes to inbox.
- Yellow — Elevated complaints, trap hits, or filtering. Outlook.com is throttling or junking some mail. Treat as a leading indicator of a block.
- Red — Outlook.com considers the IP a problem. Expect heavy junking, throttling, and likely an S3140 block within days.
When an IP goes yellow, you have a window — usually 3–7 days — to fix the underlying issue before it goes red.
Acting on JMRP Reports
Every JMRP message contains the original message in message/rfc822 format. Parse it, extract the recipient (X-HmXmrOriginalRecipient header is the safest), and:
- Add to your suppression list immediately.
- Tag the campaign or list segment that generated the complaint.
- Track complaint rate per segment — repeat offenders are usually one or two bad list sources.
Aim for a complaint rate below 0.1%. Anything above 0.3% sustained will earn an S3140 block within weeks.
Automating SNDS Monitoring
SNDS doesn't have a polished API — you fetch a tab-delimited file with a key Microsoft generates for each authorized IP. You can pull it on a cron and alert on color changes.
If you'd rather not build that, MailVitals' IP Monitoring ingests SNDS data, JMRP signals, and 34 DNSBLs into a single feed with Slack/email alerts.
FAQ
Is SNDS only for Outlook.com / Hotmail, or also Microsoft 365? SNDS data is for the consumer Outlook.com side. Microsoft 365 (Exchange Online) reputation is separate and not exposed publicly — you infer it from EOP headers and bounce codes.
My ESP owns the IPs. Should I still register? You can't — Microsoft verifies via WHOIS. Ask your ESP for their SNDS data or for a dedicated IP if your volume justifies it.
Why is my IP not in SNDS even after approval? SNDS only shows IPs that have sent enough sampled mail (typically 100+ messages/day) for Microsoft to score. Low-volume IPs simply won't appear until they hit that bar.