Free tools

DKIM checker

Queries the most common DKIM selectors (default, selector1, selector2, google, k1, mail, s1) to see if the domain publishes a DKIM key under any of them.

Why only common selectors

DKIM is published under a selector freely chosen by each mail provider. There is no way to "discover" the exact selector without access to the sending server, so we test the names most used by popular providers.

A negative result is not conclusive

If your provider uses a selector different from the ones tested, this tool will not find it even if DKIM is correctly configured.

Frequently asked questions

Quick questions about this tool

How do I find my provider's exact selector?

It usually appears in your mail provider's DKIM setup documentation, or in the "DKIM-Signature" header of an email you already sent.

What does DKIM actually do?

It cryptographically signs the email content so the receiver can verify it was not altered in transit.