User Info Retrieval API

I need a clean, well-documented API whose single focus is fetching user information on demand and returning it in JSON. Using token biased authentication. Both sides of API are well documented. Will be using RingCentral to fetch data from OpenEMR V7.
Two api's needed at this time. 1. To Authorize the conversation using tokens, 2.) fetch data from five fields on OpenEMR database.

Key points I care about
• RESTful structure—or GraphQL if you can demonstrate clear advantages
• Secure access layer and rate limiting so the API is safe for production traffic
• Lightweight, easy-to-read JSON payloads with concise field names and meaningful HTTP status codes
• Inline and external documentation (Swagger / OpenAPI preferred) so my team can start consuming it immediately
• Unit tests that prove core endpoints work and edge cases are handled

Deliverables
1. Source code in a public or private repo of my choosing
2. Deployed, working endpoint (temporary staging is fine)
3. API reference docs generated from code comments
4. Brief hand-off walkthrough so I can maintain or extend it later

If you’ve built similar user-info services before, let me see an example call or repo snippet in your bid.