DKIM record checker
Find published DKIM keys for a domain across 70+ common selectors, or enter your own selector, and verify key strength.
Free, instant, no signup. Results include SPF, DKIM and DMARC together.
How DKIM lookup works
DKIM keys live at <selector>._domainkey.<domain>. The selector is chosen by whoever signs the mail, so there is no way to list them all from DNS. This tool probes the selectors used by Google Workspace (google), Microsoft 365 (selector1, selector2), Mailchimp (k1), SendGrid (s1, s2, smtpapi), HubSpot (hs1, hs2), Zendesk, Mandrill, Postmark, Amazon SES and others. For each key found it parses the public key and reports the RSA modulus length, revoked keys (empty p=) and testing flags.
To check a specific selector, use the URL form /check/yourdomain.com?selectors=mysel, or add selectors permanently to a monitored domain.
Get told when it changes
MailAuthWatch re-checks your domains daily and alerts you on any change. From $29/month for 10 domains.
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Public checks run in the last few days. Every report is measured live from DNS when it is opened.