What Is Microsoft Smart Network Data Services (SNDS) and Do I Need It?

August 09, 2023
Written by
Serena Maffei
Opinions expressed by Twilio contributors are their own
Reviewed by
Ayanna Julien
Opinions expressed by Twilio contributors are their own
Denis O'Sullivan
Opinions expressed by Twilio contributors are their own

What Is Microsoft Smart Network Data Services (SNDS) and Do I Need It?

We all know how challenging it can be to determine the root cause of poor deliverability with a given inbox provider. However, Microsoft is different, providing powerful insights through its Smart Network Data Services (SNDS).

Here, we’ll tell you everything you need to know about Microsoft SNDS, including what it is, why you need it, and how to get it. 

First, let’s start from the beginning: what is SNDS?

What is Microsoft SNDS?

Microsoft SNDS allows email senders to access valuable email activity data. The goal is for senders to use this data, derived from the log files of the Hotmail and Microsoft mail servers, to implement best practices.



What data does SNDS provide?

SNDS provides data by IP for days where there are at least 100 messages sent. It then divides the data into days based on the U.S. Pacific Standard Time.

For each IP, SNDS displays the following data points:

Activity period

This is the period during which the IP's mailing activity occurred. 

Traffic data

RCPT commands

This is the number of commands where the sender specifies their intent to send mail to a recipient and asks Microsoft whether it’ll accept mail for the recipient. In other words, this is the number of messages sent to Microsoft by the IP. 

DATA commands

This is the number of commands that transmit messages to the recipients that Microsoft established can receive emails in the previous step. In other words, this is the number of messages accepted by Microsoft.

Message recipients

This is the number of messages that reach the recipients. In other words, this is the number of messages delivered to recipients (either in the inbox or spam folder)

Note that a large discrepancy between RCPT commands and DATA commands corresponds to a high hard bounce rate. 

While a small difference between the number of RCPT commands and Message recipients is common, this is likely due to accounts becoming inactive or other anomalies.

For example, email addresses valid at the time of reception can become invalid when Microsoft tries to deliver to the recipient. A large difference can also indicate that Microsoft may not deliver emails to recipients after accepting them due to a block or a reputation issue.

Junk mail data

Filter result

This is the aggregate result of the spam filtering applied to messages sent by the IP in the given activity period. These results don’t necessarily show what percentage of emails landed in the spam folder, but rather the percentage of messages considered to be spam by Microsoft (this is because the recipient might have rules or filters that might lead to a different classification).


Complaint reports

This is the number of complaints divided by the number of Message recipients (see above). In other words, this is the complaint rate

Note that SNDS displays complaints for the day reported, not the day delivered. Therefore, in some cases, it’s possible to see high complaint reports percentages if sending volumes were small following a big send.

Trap hits

This is the number of messages sent to spam traps maintained by Microsoft. For this metric, the times of the first and last messages sent to trap accounts is also available under the Trap message period column.

Sample messages

This is to help the sender troubleshoot. While SNDS provides sample messages for user junk reports and trap hits, it only provides one sample message per IP for both types daily. 

Learn more about spam reports.

Sample HELO command

This field provides an example HELO (or EHLO) command sent by the IP. Along with other data, this field can help confirm the sender’s identity and determine that an IP isn't spamming.


This column provides additional data about the IP (if any). For example, it might indicate that Microsoft blocked the IP due to abuse complaints.

Why get access to Microsoft SNDS data?

It’s a powerful tool to monitor your IP reputation. While reputation is inferrable through monitoring other metrics (like a drop in open rates could indicate an increase in filtering to the spam folder), there are many factors at play (like a drop in open rates could also be due to a large campaign that generated lower subscriber engagement) that make it difficult to guess the state of your reputation. 

For example, the filter results with the traffic light system are a great indicator of whether the IP has a reputation issue. At the same time, metrics such as spam complaints and spam trap hits could potentially indicate the root cause of the reputation issue.

Where do I log in to view Microsoft SNDS?

As the owner of your IPs, Twilio SendGrid has access to Microsoft SNDS data on your behalf. So if you’d like to gain access, sign up here and request access* by entering your IPs and selecting abuse@sendgrid.com as the address to receive the access request. 

Then, open a ticket with our Support team, indicating the IPs you’ve requested access for and the email address associated with your Microsoft SNDS account (alternatively, you can also reach out to your Deliverability consultant). We’ll then approve the request on our side.

Once you have access here, you can retrieve data about your Microsoft/Hotmail/Outlook email sending to make informed decisions about our deliverability.

*Note that you can only request access for 20 IPs at a time. To add more IPs, you’ll need to wait for the first set of IPs to receive access.

Resolve Microsoft sending issues and more with Twilio SendGrid

Have you noticed low open rates or blocks at Microsoft/Hotmail/Outlook? How about a yellow or red SNDS status? With a Twilio SendGrid deliverability service package, you’ll work with a deliverability expert that knows exactly how to get you back in the Microsoft inbox. 

Sign up today to get started for free and upgrade to one of our deliverability service packages.

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