I wrote a group of WebAuthn libraries in TypeScript that aims to make it as easy as possible for devs to incorporate WebAuthn into their server: https://simplewebauthn.dev/

The pair of server and browser libraries (with a third TypeScript types library) supports IE10+ and get WebAuthn down to four method calls with a small handful of arguments. And since the libraries take care of JSON serialization devs don't need to think about how to get random buffers from the server to the browser and back.

If this means anything to you the server library is FIDO-conformant. It's not FIDO certified but it's pretty darn close, and will handle just about every WebAuthn use case you can think of. There are still things the server has to do to properly incorporate WebAuthn support, but the work I've done significantly reduces most of the common stuff to a couple of libraries you can `npm install` and go.