Ask a cold email team how their Gmail reputation looks and most can answer, Google Postmaster Tools is free and widely used. Ask about Outlook and Microsoft 365 and you usually get a shrug, despite Microsoft holding a large share of B2B inboxes.
Microsoft has tools. They are older, less pleasant, IP-based rather than domain-based, and they were substantially rebuilt in mid-2026. That last part matters, because most guides still describe the old version.
The two programmes
SNDS, Smart Network Data Services. Reputation and filtering data for IP addresses you control. The closest thing Microsoft has to Postmaster Tools.
JMRP, Junk Mail Reporting Program. A feedback loop: when an Outlook.com user marks your mail as junk, you get a report.
Both are free. Both key off IP addresses rather than domains, and that single design decision determines who can use them.
The access problem, and why it decides your IP strategy
To register an IP range with SNDS you must demonstrate control of it. Approval involves a confirmation sent to an address associated with the range, the Whois contact or a conventional administrative mailbox.
Which means:
If you send on a shared IP, you cannot register it. You do not control it. Your infrastructure provider does, and they should be watching it. The right move is to ask them what their SNDS status looks like, not to try registering it yourself.
If you have a dedicated IP, you should register it. It is free and it is data nobody else will give you about the second-largest mailbox estate in B2B.
This is one of the less discussed arguments in the shared-versus-dedicated question. A dedicated IP gives you direct visibility into Microsoft’s view of you. A shared IP delegates that visibility, fine with a competent provider, and worth asking about. The shared versus dedicated threshold covers the rest of the trade-off.
One note on Microsoft 365 recipients. SNDS and JMRP reflect the consumer side, Outlook.com, Hotmail, Live. A business recipient on Microsoft 365 sits behind tenant-level filtering their own administrator configures, and no sender-side dashboard reports on that. SNDS is still a useful proxy for how Microsoft’s filtering infrastructure regards your IP, and it is a proxy rather than a direct view of corporate inboxes.
What changed in 2026
Microsoft moved SNDS to a new portal on 8 June 2026 and has been adjusting it since. If you set this up before then, several things in your runbook are now wrong. Three changes matter most:
Trap-hit counts are gone. Removed from the data report on 22 July 2026. This was arguably the most useful field SNDS offered cold senders, a direct count of how many of your sends hit spam traps, which is the fastest confirmation that a list was bad. A blank field now means unavailable, not zero.
Losing it is a real loss, and it moves the burden back to where it should have been anyway: verify before sending rather than find out afterwards.
Approved networks expire. Approval now lasts around ten months, with reminders before expiry. An IP range you registered and forgot will silently stop reporting. Put the renewal date in a calendar the day you register, this is the trap that will catch most people.
JMRP reports carry less. The complaint body is no longer included and the sender address is redacted. If your process relied on the return-path to identify which campaign and recipient a complaint came from, it needs rebuilding, the remaining headers are where to look. JMRP feeds not linked to an SNDS account with current network access were also removed and have to be recreated.
Also worth knowing: old automated access URLs were deprecated on 22 June 2026, so scripted pulls need updating, and report links now expire after 30 days. Times are reported in UTC rather than GMT, which matters only if a saved schedule assumed otherwise.
All of the above reflects the position in October 2026 and this area has been moving. Check the current portal before building a process on it.
Reading the data
IP status
A traffic-light indicator of whether your IP is filtered. Green is normal, yellow and red are not.
Red is unambiguous and usually means a volume spike, a bad list, or a compromised sending setup. Yellow is the one worth acting on, because it is early. Most teams notice Microsoft problems when replies from Outlook recipients stop, which is weeks after yellow first appeared.
Complaint rate
Complaints as a proportion of volume. The number to run at is below 0.1%, and it is the same discipline Gmail enforces at 0.3%.
High complaints with clean authentication is a targeting problem, not an infrastructure one. No amount of DNS work fixes mail that people did not want.
Filter result
What Microsoft’s filters did with your mail. This is the field to read alongside IP status, a green status with adverse filter results tells you more than either alone.
Volume
Your sending volume as Microsoft counts it. Useful mainly for one thing: comparing it to what you believe you sent. A material gap means either a configuration problem or someone else sending from your range.
A sensible monitoring setup
Weekly, five minutes:
- IP status for every registered range, anything not green gets attention today
- Complaint rate, under 0.1%
- Volume against expectation
Monthly:
- JMRP complaints reviewed for pattern, one campaign, one list source, one sequence step
- Check the renewal date on every approved network
On any change:
- New IP, new provider or a volume increase of more than about 30%, check within the week rather than the month
The weekly check is the one that earns its place. The monthly review of JMRP complaints is where you find that one list source produces most of them, which is the kind of finding that changes a list-buying decision.
SNDS alongside Google Postmaster Tools
Both, because they tell you different things.
| Google Postmaster Tools | Microsoft SNDS | |
|---|---|---|
| Keys off | Domain | IP address |
| Who can register | Anyone with DNS access | Only whoever controls the IP |
| Spam rate | Yes, with a 0.3% threshold | Complaint signal, no published threshold |
| Trap hits | No | Removed in July 2026 |
| Feedback loop | No | Yes, via JMRP |
| Reflects corporate inboxes | Partly | Partly |
Google’s is domain-level, so it works regardless of your IP arrangement and is the first one to set up. The Postmaster Tools guide covers it.
Microsoft’s is IP-level, so it depends on who owns the IP, and it adds the feedback loop Google does not offer.
Neither reflects corporate filtering properly. Both are leading indicators rather than ground truth, which is why seeded placement testing remains the only way to see where mail actually lands.
When SNDS is not the answer
Three situations where people reach for it and should not.
Reply rates are poor but all signals are green. That is a message or targeting problem. SNDS cannot see your copy.
You send on a shared IP. Ask your provider. Registering is not available to you, and that is a property of the arrangement rather than a problem to solve.
You are blacklisted. SNDS may show the effect; it is not the venue for the fix. Blacklist delisting is a separate process per list.
The short version
Microsoft’s tools are IP-based: SNDS for reputation and filtering, JMRP for complaint feedback. Both free, both significant because a large share of B2B recipients sit behind Microsoft.
You can only register IPs you control, which means shared-IP senders delegate this to their provider and dedicated-IP senders should set it up.
The 2026 rebuild removed trap-hit counts, trimmed JMRP reports and made network approvals expire after about ten months. The expiry is the trap, calendar the renewal.
Run both SNDS and Google Postmaster Tools. They key off different things, neither sees corporate filtering properly, and placement testing is still the only direct answer.
Next: Google Postmaster Tools for cold senders, or what sender reputation actually is.
Frequently asked questions
What is Microsoft SNDS?
Smart Network Data Services, Microsoft’s free reporting tool showing IP status, complaint rate, filter results and volume for IP addresses you control. It is the closest Microsoft equivalent to Google Postmaster Tools, and it keys off IPs rather than domains.
Can I use SNDS with a shared IP?
No. Registration requires demonstrating control of the IP range, which with a shared IP belongs to your infrastructure provider. Ask them what their SNDS status shows instead.
What changed with SNDS in 2026?
Microsoft moved to a new portal on 8 June 2026, deprecated old automated access URLs on 22 June, and removed trap-hit counts from the data report on 22 July. Network approvals now expire after roughly ten months, and JMRP reports no longer include the complaint body.
Do I need SNDS if I already use Google Postmaster Tools?
Yes, if you control your IPs. Postmaster Tools is domain-level and covers Gmail; SNDS is IP-level and covers Microsoft’s consumer estate, and it adds a complaint feedback loop that Google does not provide.
Sources: SNDS and JMRP in transition, Spam Resource · Microsoft SNDS 2026 changes, Suped