OAuth Grant Types Explained: Which One Should You Use?

OAuth 2.0 provides various grant types tailored to different authentication scenarios, but selecting the incorrect flow may compromise security and user experience. The Authorization Code grant is recommended for user-facing applications, ensuring secure authentication through redirect URIs, PKCE, and token management, while the Client Credentials grant is optimal for machine-to-machine interactions without user involvement. The Refresh Token grant supports token renewal for long-lived sessions without re-authentication, enhancing user experience and security. The Implicit grant is deprecated due to inherent vulnerabilities, while the Resource Owner Password Credentials grant is risky due to direct credential handling. The Device Code grant caters to devices with limited input capabilities, enabling secure cross-device authentication. SuperTokens offers support for these flows, enhancing security features like PKCE, token rotation, and third-party provider integration, except for Implicit and Device Code grants, which are either deprecated or not yet supported. The guide emphasizes the importance of choosing the right OAuth flow based on application architecture and security needs, recommending Authorization Code with PKCE for user-centric applications and Client Credentials for backend services, while cautioning against deprecated and risky options.