DKIM checker

Is this domain signing its email, and are the keys strong enough?

Live lookupPlain English + technicalFree, no sign-updkim.middle.network

How to read the results

Each card is one selector found. 2048-bit RSA or Ed25519 is the standard.
Find your selector in a sent email: the s= tag of the DKIM-Signature header.

Check everything at once

The health check runs this and 30 more checks on a domain, then ranks what to fix.

Guides for auditors

Compliance checks

Domain audit Domain security audit ISO 27001 domain compliance check SOC 2 domain security check Cyber security compliance check

More in Email authentication

SPF checkValidate SPF and count the 10 DNS lookups.
DMARC checkRead the DMARC policy and reporting setup.
BIMI checkCheck your brand logo record for inboxes.
MTA-STS checkCheck encryption is enforced for incoming mail.
TLS-RPT checkCheck you get reports when secure delivery fails.
DANE / TLSACheck TLSA records for your mail servers.
SPF / DMARC / DKIM / BIMI generatorsBuild SPF, DMARC, DKIM, BIMI and MTA-STS records.

About the DKIM check

Look up a domain’s DKIM keys at common selectors or your own, and check the key type, size and whether it is revoked or in test mode.

Every result comes in two styles: plain English for everyone, and the exact technical detail for engineers, with the raw JSON one click away.

Questions

We try common selectors. Many providers use their own; enter it in the selector box.