FIDO2 is an open authentication standard developed by the FIDO Alliance to enable passwordless login to applications through registered devices or security keys, enhancing both security and user experience. It comprises the Web Authentication API and the Client to Authenticator Protocol, supporting possession-based and biometric authentication methods. FIDO2 is widely supported across various platforms and is seen as an advancement over previous standards like U2F and UAF by providing comprehensive passwordless authentication. It enhances security by eliminating shared secrets vulnerable to attacks like phishing and credential stuffing, while also offering convenience by streamlining the login process through device capabilities such as fingerprint readers or face scans. However, challenges in its implementation include the complexity of initial setup, the cost of hardware tokens, and limited support in legacy systems. Solutions like Descope offer tools to simplify the addition of FIDO authentication to applications, providing drag-and-drop workflows to integrate biometric authentication with existing identity providers.