Free DKIM checker: look up your public key TXT record
What is a DKIM record?
DKIM (DomainKeys Identified Mail) adds a cryptographic signature to outgoing email. Receiving servers look up a public key in your DNS to verify the signature — proving the message came from your domain and was not altered in transit.
google._domainkey.example.com. TXT "v=DKIM1; k=rsa; p=MIGfMA0GCS..."
See our DKIM record guide for selector examples from Google Workspace and Microsoft 365.
Common DKIM setup mistakes
Wrong selector — the s= tag in DKIM-Signature must match the DNS subdomain you query.
Key rotation without publishing the new selector before cutover.
Missing DKIM while DMARC requires alignment — DMARC can pass on SPF alone, but both is best practice.