Enter a domain (or an email address) to check it against the domain and URI blacklists spam filters use to score the links and sender domains in a message. Lists that refuse public lookups are flagged, never guessed. Free, no sign-up.
Spammers rotate IP addresses faster than IP blacklists can follow, so filters also score the domains that appear in a message: the sender domain, every link in the body, and where those links redirect. Domain blacklists (also called URI blacklists or RHSBLs) list domains seen in spam, phishing and malware campaigns.
A listing hurts every message that mentions the domain, even when it is sent from a perfectly clean IP. The common causes are a compromised website used to host phishing pages, a link shortener or redirect abused by others, or a domain used in cold outreach that drew complaints.
The most widely used domain list. Refuses public resolvers, so it is shown with a direct-check link.
Lists of domains found in spam message bodies. Both refuse most public resolvers too.
NordSpam, Suomispam and abuse.ro, queried live and verified with their test entries.
There is no blacklist of individual email addresses: lists key on the domain after the @.
Not on DNS blacklists. They track domains and IPs. A provider may block an individual sender internally, but nothing public lists single addresses.
Find the cause first: scan your website for injected pages, check redirects and forms, and review recent campaigns. Then use the list's removal form; most require that the problem be fixed before they delist.
No. Domain blacklists affect mail that contains or comes from the listed domain, so it hurts what you send and any mail that links to your site.
Point an MCP client (Claude, Cursor, any agent) at https://powerline.ai/mcp and call check_blacklists, or hit the JSON endpoint directly. No key, no account.
curl "https://powerline.ai/api/tools/blacklist?target=example.com"
Check a sending IP against 18 email DNS blacklists, grouped by how much each one matters.
SPF, DKIM, DMARC, MX, MTA-STS, TLS-RPT, BIMI and blacklists in one run, scored out of 100 with a fix list.
Highlight spam-trigger phrases, ALL-CAPS, exclamation runs and emoji in a subject and body, with a rewrite.
Read the DMARC policy, alignment and reporting tags, and check that report addresses will accept reports.
See how your HTML email actually renders in real Gmail, Outlook.com and Yahoo Mail accounts. Free screenshots.