Okta/Auth0 Authentication and SSO Setup

Our production web application already has a mature code-base, but access control is still handled in-house. I now want to transition everything to industry-standard identity providers—Okta and Auth0—to harden security and simplify user management.

Here is what I need from you, an engineer who has done this before with real traffic:

• User authentication configuration in both Okta and Auth0, mapped cleanly to our existing user tables and session logic.
• Full single sign-on so customers can move between our companion apps without logging in again.
• Secure API token flow (OAuth 2.0 / OIDC) that protects our REST endpoints and fits our current role-based permissions scheme.

The application is built as a responsive web app (React + Node). I will give you repo access, an environment file, and Postman collections so you can test end-to-end.

Acceptance will be based on:
1. New users can register and log in through either provider.
2. Existing users migrate seamlessly without password resets.
3. SSO works across two internal sub-domains.
4. API calls reject invalid or expired tokens and honour scopes.
5. Clear hand-over notes and code comments let my team maintain the setup.

If this matches your past projects, let’s set milestones and get started right away.