sagarshelake14/Backend-Development-Basics ? reverse-engineered prompt

Build me a simple MERN style backend project that teaches the basics of real backend development.

I want a Node and Express app connected to MongoDB, with clean REST APIs for creating, reading, updating, and deleting data. Include user signup and login, password hashing, JWT based authentication, protected routes, and a couple of role based checks so I can see how authorization works. Add good middleware for validation, error handling, and basic API security. Keep the code organized in a way that is easy to understand and learn from, because this is mainly for practicing backend concepts.

Please also make it easy to test with Postman and include environment variable setup for local development. If you need to look up current docs online while building it, feel free to do that. The goal is not just to have code that runs, but to have a small backend I can study and improve as I learn more.