Right now APIs for third parties are fairly limited, so it can be difficult to have support for passkeys with password managers. I was able to solve it for Bulw

Right now APIs for third parties are fairly limited, so it can be difficult to have support for passkeys with password managers. I was able to solve it for Bulwark Passkey (https://bulwark.id https://bulwark.id) by emulating a USB device and building the WebAuthN protocol off of that. This means that it supports all browsers, but also means that iOS support will be more difficult, though not impossible.