I have dreamed about a cross-platform application to securely authenticate a user's login. I developed KH Authenticator, a .NET MAUI App for Windows and Android which registers and authenticates a user without a password or email address. I imagine many KH Authenticator account providers. The Developer Role grants access to the portal which supports the vision. Developers can create sandbox providers and access preview versions of the KH Authenticator application. Sandbox providers are listed in apps where the Primary Provider is joined to the Developer account. Members (registered users) may request the Developer Role.
I researched and developed the Users Without Passwords Project (UWPP) which implements WebAuthn, also known as FIDO2, instead of passwords. WebAuthn is more secure and multi factor by design. The UWPP and the Users With Device 2FA Project (UWD2FAP) implement WebAuth. Basic password authentication is familiar and difficult to replace with WebAuth. WebAuth requires the user to possess a FIDO2 device like Windows Hello, mobile lock screen, or a security key.
The UWPP published at UsersWithoutPasswords.Com, the UWD2FAP published at UsersWithPasswords.Com, the Users Without Identity Project (UWIP) published at UsersWithoutIdentity.Com, and the Users With Comments Project (UWCP) published at Preview.KenHaggerty.Com implement the KH Authenticator API. The projects are available for download from KenHaggerty.Com which also supports the KH Authenticator API.