Free tool · DNS check

DKIM Record Checker

Check the DKIM public key a sender publishes for a selector: key type, size, revocation and testing flags.

How it works

What gets checked

DKIM keys live at <selector>._domainkey.<domain>. We fetch that TXT record, parse its tags, validate the base64 public key, and measure an RSA key’s size.

Limits

What it cannot tell you

  • It reads public DNS through a DNS-over-HTTPS resolver. It does not send mail and cannot say whether a message will be delivered or pass authentication.
  • You must know the selector; DKIM selectors cannot be discovered from a domain alone. Your sending service shows which one it uses.
  • It checks the published key, not whether your messages are signed correctly.
  • Anonymous use is limited to 30 checks per hour.
FAQ

Common questions