Free tool
Blacklist checker.
Even perfect SPF, DKIM, and DMARC will not save you if your sending IP is already listed on a DNS-based blacklist (DNSBL). Enter a domain to resolve its mail-sending IP and check it against Spamhaus ZEN, SpamCop, and Barracuda.
Run the check
We resolve your sending IP
A server-side MX/A lookup for the domain you enter — no signup, nothing stored.
We query three DNSBLs
Spamhaus ZEN, SpamCop, and Barracuda — the blacklists most receivers actually consult.
You get a clear verdict
Listed on any of the three is a fail — receivers reject or spam-folder that IP regardless of SPF/DKIM/DMARC.
Other free checks
SPF checker
Look up and grade your SPF record — policy strength, multiple-record errors, and DNS-lookup limits.
DMARC checker
Check your DMARC policy, enforcement level, and reporting — the records Gmail and Yahoo now require for bulk senders.
Spam-word checker
Scan a subject line and body for common spam-trigger phrases like "act now" and "100% free" before you send.
CogniLead runs on a warmed sender pool with a reputation circuit-breaker that pauses a domain before it ever reaches a blacklist. You bring the leads.