How can I check my sender reputation?

There's no single dashboard that shows your reputation across all mailbox providers. Each one (Gmail, Outlook, Yahoo) keeps their own scores and only shares fragments of the data. So checking your reputation means visiting multiple free tools and reading the signals they expose.

Here's the actual walkthrough for the two tools that matter most:

Google Postmaster Tools (for Gmail reputation)

Google Postmaster Tools shows you how Gmail sees your domain and IP reputation. You'll need to verify domain ownership first (add a DNS TXT record or upload an HTML file to your site).

Once you're in, look at the Domain reputation chart. It'll show High, Medium, Low, or Bad. High is good. Medium means you're sliding. Low means Gmail is filtering you hard. Bad means you're in the spam folder by default.

The IP reputation chart shows the same scale but for your sending IP. If you're on a shared IP (most ESPs use shared), this reflects everyone on that IP, not just you. That's why dedicated IPs exist, but don't rush to get one unless you're sending high volume (50k+ emails per day).

Also check the Spam rate chart. Gmail's cutoff is 0.3%. Above that and your reputation tanks. Keep it under 0.1% if you can.

Now one catch: Google Postmaster only shows data if you send enough volume to Gmail addresses. If you're sending under a few hundred emails per day to Gmail, the charts will stay blank. That's normal.

Microsoft SNDS (for Outlook/Hotmail reputation)

Microsoft SNDS (Smart Network Data Services) shows how Outlook, Hotmail, and other Microsoft properties see your sending IPs.

You'll need to register each sending IP you use. Once registered, SNDS gives you a color code:

• Green: Good reputation. Your mail gets through.
• Yellow: Moderate issues. Some filtering is happening.
• Red: Bad reputation. You're being heavily filtered or blocked.

SNDS also shows spam trap hits and complaint rates. If those numbers are climbing, your reputation is about to drop.

One limitation: SNDS only tracks IPs, not domains. If you're on a shared IP, you're seeing the reputation of everyone on that IP, not just your sending.

What if you can't access these tools?

Still if you're on a shared IP and your ESP won't tell you which IPs they use, you can still infer reputation from your own metrics. Watch your inbox placement rate (if your ESP tracks it), your open rate trends (drops usually mean spam folder), and your bounce rate. A sudden spike in bounces or a drop in opens means something changed with your reputation.

You can also check if your domain or IP is on public blocklists. We built a free blocklist checker that scans the major lists (Spamhaus, Barracuda, SORBS) in one go. Being listed doesn't always mean disaster (some lists are barely used), but if you're on Spamhaus, that's a red flag.

Want to know what actually drives these scores? Or what tanks reputation fastest? Check those next.