How do you check if your domain is blacklisted?

The short answer

Run your sending domain and its mail server IP through a free blacklist checker such as MXToolbox, then open Google Postmaster Tools to see how Gmail rates you. A listing is one reason cold emails land in spam, not the only one, so a clean result doesn't prove your placement is fine. Prices below are as of October 2026.

How we research this: facts come from each vendor’s public pages and named studies, dated where shown; the math is ours and labeled. Vendor prices and limits are as of October 4, 2026.

Updated

What's the fastest way to check?

Five steps, all free:

  1. Find what you send from. Your sending domain is the part after the @ in your From address. The IP is in the headers of a test email you send to yourself.
  2. Run the blacklist check. Per MXToolbox, the check runs a mail server's IP against 100-plus DNS-based blacklists, and you can type in a domain as well as an IP. Paste the domain, then the IP.
  3. Read the result. A listing tells you which list flagged you. Removal rules differ by list, so follow the steps on that list's own site.
  4. Open Google Postmaster Tools. Add your sending domain, verify it with a DNS record, and read the spam rate, reputation, authentication and delivery error dashboards. Google notes it only reflects mail sent to personal Gmail addresses.
  5. Check authentication. SPF, DKIM and DMARC records should all pass before you worry about anything else. See how to run an inbox placement test.

In our view, if you send through a mailbox provider such as Google Workspace, the sending IP is usually the provider's, so the parts you control are your domain and your sending habits. That's our view, not a measured rule.

What do the free tools tell you?

Tool What it checks Limit
MXToolbox blacklist check A server IP or domain against 100+ DNS blacklists A snapshot at the moment you run it
Google Postmaster Tools Spam rate, reputation, authentication, delivery errors Gmail data only; you must verify the domain with a DNS record
GlockApps Free 2 spam test credits, 1 IP reputation monitor, 5 uptime monitors Two tests, then you pay

Google's target, per its sender guidelines: a Postmaster Tools spam rate under 0.10%, and never 0.30% or more. If your number is climbing, stop adding new prospects and look at your list before your copy. Should you buy an email list? shows why.

When is a paid monitor worth it?

When you send from several domains and want alerts instead of manual checks. Here are the three we looked at.

Tool Price (as of October 2026) What it includes for blacklists and health
MailReach $25 per mailbox per month at 1 mailbox on monthly billing, priced by mailbox count; 20% off billed annually Warmup for the mailbox, 20 spam test credits, a reputation dashboard, and domain and inbox health checks covering blacklist, SPF, DKIM, DMARC
GlockApps Essential $85 a month, or $59 a month billed yearly 30 spam test credits a month on monthly billing, 10 IP reputation monitors, 15 uptime monitors
Warmy Plans from $49 a month, by volume A reputation tracker with blacklist alerts, a deliverability tester that includes a blacklist check, and DMARC monitoring. See is Warmy worth it?

For one rep with 4 inboxes on 2 domains (our house plan), start with the free checks every Monday. Pay for a monitor only after a listing or a spam-rate spike. Warmup and placement tools also appear in best email warmup tools.

What should you do if you're listed?

  1. Pause sending from that domain. Keep sending and you add complaints.
  2. Find the cause. Look at your last list, your bounces and your volume. Cleaning the source matters more than getting removed.
  3. Request removal on the list's own site. Each list sets its own rules and timing.
  4. Restart small. Send to your best, verified contacts first and rebuild from there. Cold emails per day per inbox covers volume.

A separate sending domain protects your main one. See should you use a separate domain for cold email?.

The sending days, sends per inbox, inboxes per rep and touches per contact on this page are our house assumptions, with one line on why we use each.

Sources

Research and vendor pages accessed October 1, 2026.

Frequently asked questions

How can I tell if my domain is on a blacklist?

Paste both the domain and the sending IP into a free checker such as MXToolbox. If a list flags you, the result names it. Also check Google Postmaster Tools for a rising spam rate.

Is checking a blacklist free?

Yes. MXToolbox's blacklist check, Google Postmaster Tools and GlockApps' free plan cost nothing. Paid monitors add alerts and repeat tests.

Can a blacklisted domain still reach the inbox?

Sometimes. Blacklists are only one input, and mailbox providers use their own signals. That's why you should also check placement and authentication.

How often should I check?

Weekly for an active sending domain, and any time replies or opens drop. If you have several domains, a paid monitor with alerts saves time.

Why do sending domains end up on blacklists?

Common causes are bad lists, high bounce rates and spam complaints. Verified lists bounce less than bought ones, so verify before every send. Our guideline is to pause above a 2% bounce rate; Google and Microsoft publish no bounce threshold.

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