Look up DKIM (DomainKeys Identified Mail) records for any domain. DKIM uses cryptographic signatures to verify that an email was sent by an authorized server and was not modified in transit. Enter a domain and optionally a selector, or leave the selector blank to auto-detect common selectors.
DKIM (DomainKeys Identified Mail) adds a cryptographic signature to outgoing emails that receiving servers can verify against a public key published in DNS. This proves two things: the email actually came from the domain it claims to be from, and the message body was not modified in transit. DKIM uses selectors to allow multiple signing keys per domain, which is common when different email services (Google Workspace, Microsoft 365, Mailchimp, SendGrid) send on your behalf. This tool looks up DKIM public key records for any domain by querying the selector._domainkey.domain.com TXT record, and can automatically scan common selectors to detect which email providers are configured.
Enter a domain name and optionally a DKIM selector. If you know the selector (check the DKIM-Signature header in a received email, look for the s= field), enter it for a direct lookup. If you do not know the selector, leave it blank and the tool will automatically probe common selectors used by major email providers including Google, Microsoft, Mailchimp, SendGrid, Amazon SES, Postmark, and others. Click any detected selector to see the full record breakdown including key type, key size, flags, and service restrictions.
To find the exact DKIM selector your domain uses, view the source of any email sent from your domain and look for the DKIM-Signature header. The s= field contains the selector name. For Google Workspace, the default selector is "google." For Microsoft 365, it is "selector1" or "selector2." Use 2048-bit RSA keys when possible — some older DNS providers limit TXT records to 255 bytes, which forces 1024-bit keys, but most modern providers support longer records. If you see a CNAME instead of a TXT record, the DKIM key is hosted by your email provider and managed automatically. Rotate keys periodically and avoid the "t=y" testing flag in production.
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