The Authorization Code Grant flow is a widely used method in OAuth 2.0 that enables users to securely authenticate with third-party applications by redirecting them to an authorization server, obtaining an authorization code, and then exchanging that code for an access token. This process involves several steps including setting up the authorization request, handling the redirect, exchanging the authorization code for an access token, and using the access token to authenticate API requests. FusionAuth's sandbox environment provides a simple example of this flow, allowing developers to easily integrate authentication into their applications while minimizing the risk of sensitive data being spread across multiple applications. The use of FusionAuth also enables the addition of features like profile management, Multi-Factor Authentication (MFA), and session management without burdening the application, making it an attractive solution for enhancing user experience with passkeys.