Microsoft SNDS

Microsoft SNDS is a free web portal for senders and internet service providers that need to see how Outlook.com evaluates their sending IPs. It suits operators responsible for email infrastructure and Outlook.com consumer traffic, especially those investigating reputation or abuse signals. Its provider-specific data is useful, but it is not a complete deliverability-monitoring system.

Overview

SNDS combines detailed information about individual IP addresses with a view of the overall health of an IP space as Outlook.com sees it. That makes it a focused diagnostic service for organizations managing their own sending ranges. Sender-reputation and blocklist monitoring are included, while inbox-placement and spam-trap monitoring are not.

The portal also includes Microsoft’s Junk Email Reporting Program. Senders can configure feedback-loop settings and receive reports when Outlook.com users mark messages as junk. Keeping IP data and feedback controls in one web service is convenient for Outlook.com operations, but the scope remains limited to Microsoft’s consumer mailbox environment.

Key features

IP and reputation data

SNDS exposes data for individual IPs and provides context on the wider IP space. For an ISP or mail operator, that level of granularity can connect a reputation problem to a particular address or network rather than treating all traffic alike. Blocklist monitoring adds another signal for identifying delivery risks.

Microsoft says SNDS can help IP owners detect compromised servers, malware, viruses, and botnets. This makes the service relevant not only to campaign teams but also to infrastructure and security staff responsible for protecting outbound mail systems. It cannot, however, show whether messages reach inboxes, and it does not provide spam-trap monitoring.

Junk reports and feedback controls

The Junk Email Reporting Program can send reports after recipients classify messages as junk. Managing those settings alongside IP data gives senders a direct way to follow complaint signals at Outlook.com. It is a practical feedback loop for that audience, not a cross-provider complaint or placement analysis tool.

Access and data changes

Access requires a Microsoft Account and an authorization request for the IPs you are responsible for. Network access expires 10 months after approval or migration, so ownership must be reattested periodically. Microsoft also stopped including trap-hit counts in Data Reports on July 22, 2026, an important limitation for anyone expecting those reports to support spam-trap analysis.

API access is available, which can help teams incorporate SNDS data into their own operational workflows. For urgent Outlook.com delivery problems, Microsoft advises contacting sender support with someone familiar with both the issue and the email infrastructure.

Pricing

There is one free plan, with no paid tier or seat, message, or retention allowance stated. That makes SNDS a low-risk addition for any eligible sender, but the absence of inbox-placement and spam-trap monitoring means a free account cannot replace a broader deliverability platform.

Platforms

SNDS is delivered through the web. Users sign in with a Microsoft Account, complete IP-ownership authorization, and can use the available API when integrating data into other systems.

Who it's for

Choose SNDS if you send mail to Outlook.com consumers and are accountable for the relevant IP addresses. ISPs, mail-service operators, and security teams can use its IP-level reputation, blocklist, junk-report, and abuse signals to investigate problems in their infrastructure.

It is a weaker fit for marketers or agencies needing inbox-placement tests across providers, spam-trap detection, or a unified view of multiple mailbox ecosystems. Those users will need another service alongside SNDS.

Pros and cons

• Pros: Free access to Outlook.com IP data; detailed individual-IP and IP-space visibility; sender-reputation and blocklist monitoring; Junk Email Reporting Program and feedback-loop controls in one portal; API access; signals that can reveal compromised infrastructure.
• Cons: Outlook.com-specific rather than cross-provider; no inbox-placement monitoring; no spam-trap monitoring; IP access requires authorization and expires after 10 months, requiring reattestation; trap-hit counts are no longer in Data Reports from July 22, 2026.

Alternatives

For a broader email deliverability category, see Email Deliverability Software.

• EasyDMARC is a better choice when you need API and web access plus a free plan covering 1,000 emails per month, one domain, 14 days of data history, and one invited user.
• Folderly suits teams seeking inbox-insight testing, including a free plan with two tests per month and a free real-time-alerts plan.
• GlockApps is preferable for spam testing and broader monitoring: its free plan includes two spam-test credits, 10,000 DMARC messages, unlimited DMARC domains, five uptime monitors, one IP reputation monitor, and one user.
• Postmark fits senders that need an email-delivery service as well as monitoring, with a free plan for 100 emails per month, no overages, and no expiration.
• DMARC Report is aimed at DMARC analysis, offering a free Core plan with 10,000 monthly messages, one domain, subdomains, 30 days of history, and aggregate reports.
• Suped offers web-based monitoring with a free plan covering 1,000 emails per month, one domain, 14 days of retention, unlimited users, and email support.
• TrueSend is an alternative for sending workflows, with a free plan of 6,000 emails per month, two sending domains, unlimited email IDs per domain, a drag-and-drop builder, more than 50 templates, basic analytics, and SPF.
• Unspam.email is suited to occasional testing, with a no-account tier offering three spam tests, two inbox placements, one device preview, and 24-hour data retention per month.

Verdict

Microsoft SNDS is the right choice for an Outlook.com-focused sender or ISP that wants free IP reputation data, blocklist signals, and feedback-loop management with API access. Look elsewhere, or pair it with another tool, if inbox placement, spam-trap detection, or reputation coverage beyond Outlook.com is central to your work.