The blog outlines how to integrate Descope, an OpenID Connect (OIDC) provider, into a Firebase/Google Cloud Platform (GCP) Identity application to manage authentication using passkeys, which offer multi-factor authentication through inherence and possession factors. This integration allows Descope to act as a federated identity provider, while Firebase remains the primary identity provider, facilitating the creation of new users in the Firebase directory and offering two login processes for existing users: passkeys or email. The guide explains setting up Descope as an OIDC provider in Firebase, building a login page using either FirebaseUI or custom SDK functions, and embedding Descope flows in the application. It covers handling user account linking to prevent duplicate records, ensuring a unified login experience across different identity providers. The blog emphasizes the seamless integration of Descope with Firebase, providing developers with flexible options for secure user authentication and smooth user experience, while encouraging further exploration of Descope's capabilities for mobile applications.