A very basic APEX application showing how you can use a Passkey to Sign In to a APEX application. I developed this using the Windows Hello passkeys. So I'm sure that it works with that type of Passkeys, but I confirmed that it also worked on a Samsung and an Apple phone. I've heard that it also working on MacOS, no guarantee for a Macintosh or a (removable) FIDO device.
To use it you first have to Sign In with one of the other two methods available in this App, probably the Open Door Method
Once Signed In you can "register" as Passkey for that User on your current device.
After registering you can use that stored Passkey to Sign In, if you are using that same device.
P.S. Register is the only page in this App which requires you to be authenticated.