DKIM Key Checker

Look up a domain's DKIM selector and inspect the published public key — is it valid, strong, and out of testing mode? No account required. We run the same engine the OnlyDMARC platform uses.

Enter a domain to check

We'll look up the DKIM key at {selector}._domainkey.{domain} and check whether it's published, valid, strong, and out of testing mode.

May be a subdomain, like mail.example.com.

  Not sure which selector? Look in the s= tag of a DKIM-Signature: header on an email you sent — or leave it blank and we'll probe common selectors for you.

  Free — no account, no sign-up. Runs the same engine as the OnlyDMARC platform. For abuse-prevention we keep only your IP and the domain you check, then anonymise it.

See a sample result: healthy key testing mode revoked key