ReaperCloud

DKIM Lookup

DKIM keys have no directory. If you don’t know the selector, we’ll try 100 common ones at once and tell you what we find.

Try github.com, paypal.com or google.com with a selector

Why DKIM is awkward to check

There is no index

SPF and DMARC live at fixed names, so you can always find them. DKIM does not: the selector is chosen by whoever signs the mail and only appears in the s= tag of a signature. Nothing in DNS lists them.

So we guess, in parallel

Providers use predictable names — selector1 for Microsoft 365, google for Workspace, k1 for Mailchimp. We try 100 of them in a single sweep.

Nothing found is not proof

A custom selector cannot be guessed, so an empty result means “not at these names”, not “no DKIM”. The definitive answer is in a message you actually sent.

What we grade

Key type and size against RFC 8301, keys revoked with an empty p=, and t=y testing mode — which tells receivers to ignore failures, and is the most common thing left switched on by mistake.