Web Authentication and Passkeys cookbook

I show a passkey sign-in button to every visitor, and on some browsers or older phones, tapping it just throws an error instead of doing anything.

I don't own a security key or a second phone, so I can't tell if my passkey code actually works before I ship it.

My signup form only takes a password, and I want to let new users set up a passkey too without tearing the form apart.

Every navigator.credentials call that fails throws the same kind of error, and my catch block just shows one generic 'something went wrong' no matter what actually happened.

I wired up conditional UI exactly like the docs show, and on some browsers the saved passkey never appears in the username field at all.

Passkey sign-in worked every time on my machine, then the exact same code threw an error the moment I pushed it to the real domain.

Someone opens my site on a borrowed laptop with no synced passkey on it, and the sign-in screen just sits there with nothing they can click.