Email Tools

DKIM Checker

Check whether a domain publishes a DKIM key that lets receivers verify its email signatures.

Free & instant No signup How to use FAQ

Leave the selector blank to check a list of common selectors automatically, or enter a known selector for a precise check.

Not sure what to enter? Try an example: github.com

Enter a domain to look for DKIM keys under common selectors, or add your own selector if you know it.

What is DKIM?

DKIM (DomainKeys Identified Mail) adds a digital signature to outgoing email. The public key that verifies it is published as a TXT record at selector._domainkey.yourdomain. This checker looks up that key - under the selector you enter or a list of common ones - to confirm DKIM is set up.

How to check a DKIM record

Enter the domain in the box above.
Optionally enter the selector your email provider uses (for example google or selector1); leave it empty to try common selectors.
Click Check DKIM and confirm a public key (p=...) is found.
If nothing is found, generate the DKIM key in your email provider's admin panel and publish the TXT record it gives you.

Related checks

To check SPF, use the SPF Checker.
To see which selector signed a real message, paste its headers into the Email Header Analyzer.

Rotate DKIM keys every year or so and remove selectors for email services you have stopped using. JustChecker watches your DNS, so you will know if a DKIM record is deleted by mistake.

Frequently Asked Questions

Open an email you sent, view the original message and find the DKIM-Signature header: the s= value is the selector (for example google or s1).

Either DKIM was never turned on in your email provider, the selector differs from the common ones (enter it), or the TXT record was added at the wrong DNS host.

Yes. Gmail, Yahoo and Outlook now expect both, and DMARC works best when DKIM passes, because DKIM survives email forwarding while SPF often doesn't.

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