About the DKIM Checker
DKIM adds a cryptographic signature to every message. The public key is published in DNS at selector._domainkey.yourdomain. The selector is chosen by your email provider — for example google for Google Workspace or selector1 and selector2 for Microsoft 365.
Enter a selector to check it directly, or let us try the most common selectors. Keys should be RSA 2048-bit (or Ed25519); 1024-bit keys are considered weak.
What is DKIM?
DomainKeys Identified Mail adds a cryptographic signature to every message. The public key is published at <selector>._domainkey.<domain>. The selector is chosen by your email provider and appears in the s= tag of the DKIM-Signature header.