yashn2903/Authentication-App-MERN ? reverse-engineered prompt

Build me a simple user authentication app with a login and registration flow using React on the front end and Node, Express, and MongoDB on the back end.

I want users to be able to sign up, log in, and see clear success and error messages. Please make the forms validate input before sending it, then send the data to the server, store the user safely in the database, and use secure password hashing and JWT based login. Set it up so the front end talks cleanly to the API, and handle environment variables the usual way with a local env file. If you need to check current docs for any of the libraries, go ahead and look them up online.

Keep the app straightforward and easy to run locally, with the full flow working from React to the API to MongoDB and back.