Domain reputation checker

Enter a domain. We check it on the domain blocklists, then check the IPs of its web and mail servers on the IP blocklists, all in one pass.

Enter a domain. We check the name and up to four of the addresses behind it, and show every list that answered.

What we check, and on which lists

A domain has two reputations on the public lists. Domain blocklists name the domain wherever it appears, in a From address or in a link inside the message. IP blocklists name the servers. Our single-target blacklist checker runs one or the other. This tool runs both, for the domain and the servers it depends on.

Target	Lists queried	Why it matters
The domain	Spamhaus DBL, SURBL, NordSpam DBL	Filters check every domain in the From line and in links
Web server IP (A record)	Spamhaus ZEN, SpamCop, Barracuda and five more	Shared or compromised hosting shows up here
Mail server IPs (MX hosts)	The same IP lists	Shows whether your inbound servers are flagged

The zones queried are the public DNS blocklists in our resolver, September 2026.

Blocklists are half of reputation

A public blocklist is a yes-or-no answer anyone can read. The other half lives inside each mailbox provider, and they publish it only to you. Google Postmaster Tools shows your spam rate and authentication results for Gmail. Microsoft SNDS shows how Outlook rates each of your sending IPs. Both are free once you verify the domain.

Clean on every list and still landing in spam? The provider dashboards are where you'll see why. Authentication is the usual first suspect, so run the domain health check too.

Which addresses we check behind a domain

We resolve the domain's A record for its web server and each MX host for its mail servers, then check up to four unique IPv4 addresses. You get the servers that matter for reputation without running each one through a separate tool.

Your sending IP may be neither. If you send through Mailchimp, SendGrid or your own relay, find the sending IP in the Received headers of a message you sent, then check it in the blacklist checker and confirm its PTR in the reverse DNS lookup.

Bounces are the reputation cost you control

Complaints depend on your content and your audience. Bounces depend on your list, and a list decays whether you mail it or not. Every address that returns a 550 tells the receiver you didn't check before you sent, and your domain reputation pays for it.

ZapBounce checks each address with its own SMTP check on port 25 and closes before DATA, so the check itself never sends mail. Results come back valid, invalid, catch-all or unknown, and unknowns and duplicates are never billed. 10,000 checks cost $25 on the pricing page, and credits never expire.

Questions people ask

How do I check my domain's email reputation?

Start with the public blocklists: this tool checks the domain on domain blocklists and the IPs of its web and mail servers on IP blocklists in one pass. Then read the provider dashboards, Google Postmaster Tools for Gmail and Microsoft SNDS for Outlook, which show how those providers rate your mail.

What is the difference between domain and IP reputation?

IP reputation belongs to the server address your mail leaves from; domain reputation follows your domain across every IP and every sending service. Gmail and Outlook track reputation per domain as well as per IP, which is why moving to a new IP rarely fixes a reputation problem.

What hurts a domain's reputation?

Spam complaints, mail to spam traps, and bounces from addresses that do not exist. Google's sender guidelines ask bulk senders to keep the spam rate in Postmaster Tools below 0.1% and never let it reach 0.3%. Bounces are the one of these you can remove before you send.

How do I get my domain off a blocklist?

Fix the cause first, then use the removal form of the list that named you. Spamhaus, SpamCop and the others each publish their own process, and the reason text in the result usually links to it. Requesting removal while the cause is still live tends to end in a relisting.