Free DKIM Record Checker
Validate your DKIM record and public key configuration for any selector.
What is DKIM?
DKIM (DomainKeys Identified Mail) is an email authentication method that allows the receiver to verify that an email was sent by the domain it claims to be from and hasn't been modified in transit.
How this check works
This tool queries the DNS TXT record at {selector}._domainkey.{domain} and parses the DKIM public key. It validates key type (RSA or Ed25519), key length, and record syntax against RFC 6376. If the record is found, key strength is assessed — keys shorter than 1024 bits are flagged as weak.
Limitations: This check verifies the published public key, not actual email signatures. It cannot confirm that outgoing emails are being signed correctly or that the private key matches. You must provide the correct selector — if the selector is wrong, the lookup will fail even if DKIM is properly configured.
How DKIM Works
- The sending server signs the email with a private key
- The signature is added to the email headers
- The receiving server looks up the public key in DNS using the selector
- The signature is verified using the public key
Finding Your DKIM Selector
DKIM selectors are specified by your email provider. Common selectors include:
- Google Workspace:
google - Microsoft 365:
selector1,selector2 - SendGrid:
s1,s2 - Mailchimp:
k1
Example DKIM Record
v=DKIM1; k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQ...