Email diagnostic tools
Free tools for checking how a domain sends and receives email. No signup, no limits beyond basic abuse protection.
Not sure where to start?
Authentication
- SPF checkerIs my SPF record valid, and is it under the 10-lookup limit?RFC 7208
- DKIM checkerIs the DKIM key for my selector published correctly?RFC 6376, RFC 8301, RFC 8463
- DMARC checkerWhat happens to mail that fails authentication, and will I get reports?RFC 9989, RFC 9990
- DMARC report analyzerWho is sending email as my domain, and is it authenticated?RFC 9990, RFC 9989
- BIMI checkerIs my domain ready for its logo to appear in inboxes?BIMI (Internet-Draft), RFC 9989
Delivery and transport
- MX lookupWhich servers receive mail for my domain, and do they resolve?RFC 5321, RFC 7505
- SMTP and TLS testDo my mail servers accept encrypted connections with a valid certificate?RFC 3207, RFC 8996
- MTA-STS checkerWill senders enforce TLS for my domain, and is my policy safe to enforce?RFC 8461, RFC 8460
- TLS-RPT checkerWill I get reports when senders can’t connect to my mail servers securely?RFC 8460
- Reverse DNS lookupDoes my sending server have valid reverse DNS?RFC 1035, RFC 1912
- IP blocklist checkerIs my mail server’s IP address on a blocklist?RFC 5782
- DNS propagation checkerHas my DNS change reached the resolvers that matter?RFC 1034, RFC 2308