Adding Okta SSO to a React app: SAML and OIDC walkthrough

Integrating Okta Single Sign-On (SSO) into a React app requires choosing between two protocols: OpenID Connect (OIDC) and Security Assertion Markup Language (SAML), depending on the needs of the application. For Vite-based React single-page applications (SPAs), Okta recommends using OIDC with the Authorization Code and Proof Key for Code Exchange (PKCE) flow, as it operates entirely in the browser and requires no backend. However, SAML is necessary when an enterprise customer or identity provider mandates it, as it involves server-side validation of a signed XML assertion, necessitating a backend service provider. The setup includes configuring both Okta and the React app for the chosen protocol, with considerations for when a managed authentication platform might be a more straightforward solution. The guide specifically targets Vite and React 18 or 19 apps, excluding React Native and server-rendered frameworks. OIDC remains the default and modern choice due to its ease of implementation and maintenance, while SAML is reserved for specific enterprise requirements. A managed platform can offer a seamless experience when multiple identity providers or protocols are involved, handling complexities like certificate rotations and multi-tenant configurations.