Free tool
Blacklist checker.
Enter a domain or IP to check against major email blacklists.
What are blacklists?
Email blacklists (DNSBLs) are databases of IPs and domains known to send spam. Major email providers check these before accepting mail.
What gets you listed
High bounce rates, spam complaints, sending to honeypots, missing authentication, and sudden volume spikes.
How to delist
Fix the root cause first. Then visit each blacklist's website and follow their removal process. Most take 24-72 hours.