Email blacklist check
A blacklist check queries the major public blocklists to see whether a domain is listed. Spamhaus DBL, SURBL and SpamCop are consulted by a large share of the internet's mail servers, so a listing on any of them can stop delivery almost entirely until it is resolved.
Free, no account. Ten lookups a minute per IP.
How a domain ends up listed
Three causes account for almost all listings. A spike in hard bounces, which signals a list that was bought or scraped rather than earned. Recipient complaints above the threshold the provider tolerates. And mail arriving at spam traps, which is conclusive evidence of scraped or purchased addresses.
A shared sending IP adds a fourth: you can be listed for the behaviour of other senders on the same address. That is the strongest argument for a dedicated IP once volume justifies it.
Getting delisted
Each list runs its own process. Some expire automatically after a quiet period, some require a request with evidence that the underlying cause is fixed, and a few will not delist repeat offenders quickly at all.
The order matters: fix the cause first, then request delisting. A request submitted while the bounces are still happening produces a second listing shortly afterwards, and repeated requests without remediation make a domain harder to clear.
Reading an unavailable result honestly
Blocklists return an error code — usually in the 127.255.255.x range — when they refuse a query rather than when a domain is listed. Spamhaus in particular refuses queries from open resolvers, which most datacenter IPs are.
A checker that treats any DNS answer as a listing will therefore tell clean domains they are blocked. This tool reports a query it could not actually perform as unchecked rather than as a pass or a failure, because a false positive here sends people chasing a problem that does not exist.
Common questions
- How do I know if my domain is blacklisted?
- Query the major blocklists directly. Paste your domain into the tool above and it checks Spamhaus DBL, SURBL and SpamCop. A listing on any of these is enough to disrupt delivery broadly, because a large share of mail servers consult them in real time.
- Why is my domain on a blacklist?
- Usually a spike in hard bounces from a stale or purchased list, recipient spam complaints above the tolerated rate, or mail hitting spam traps. A shared sending IP can also get you listed for another sender's behaviour on the same address.
- How do I get removed from an email blacklist?
- Fix the cause first, then request delisting through that specific list's process. Some listings expire on their own after a period of clean sending. Requesting removal while the bounces or complaints continue simply produces another listing and makes future requests slower.
- Does a blacklist check prove my email will be delivered?
- No. Not being listed removes one obstacle, but authentication, reputation, engagement and content all still decide inbox placement. Conversely, a listing is a near-complete explanation for a sudden collapse in delivery, which makes it the right thing to check first.
Check everything at once
This page covers one record. The full deliverability audit runs MX, SPF, DKIM, DMARC and blocklists together and scores the domain — or read the glossary entry for the concept behind this check.
You audited one domain. Cold outreach means thousands.
This tool checks a domain you type in. It will not tell you which addresses at that domain are real.
- Bulk mailbox verification with real SMTP checks
- The email finder — name plus company to a verified address
- Website enrichment for emails, owner names and socials
One plan, cancel anytime, no contract. The free tools stay free and unmetered either way — they are not a trial.