Free monitoring tool
DKIM Checker
Look up a DKIM public-key record using your domain and a selector supplied by your email provider.
You need the signing selector
Find s= and d= in a real email’s DKIM-Signature header, or ask your email provider. The selector chooses a public key at selector._domainkey.domain. There is no universal way to discover every selector for a domain.
Record presence is not message verification
A TXT answer at the selected name is a useful setup clue. This tool does not verify an email signature, validate key strength or prove that a message passed DKIM. An empty p value can indicate a revoked key.
When no key appears
Check selector spelling, the signing domain and provider setup. Some providers use a CNAME to their key location. Confirm that the delegation resolves and allow existing DNS caches to expire after changes.
Common questions
Can I leave the selector blank?
No. The tool requires a selector and does not guess common provider selectors.
Does a DKIM record guarantee DMARC alignment?
No. DKIM must pass for a particular message and its signing domain must align with the visible From domain under the applicable DMARC rules.