User Authentication(Login-Registration) App

A User Authentication (Login & Registration) application built using the MERN stack (React, Express, Node.js, MongoDB Atlas).

This project demonstrates how client-side and server-side APIs work together, including:

• Sending data from React frontend to Express backend
• Validating requests using Joi
• Secure password hashing with bcrypt
• Authentication using JWT (jsonwebtoken)
• Storing and retrieving user data from MongoDB Atlas
• Managing environment variables with dotenv
• Handling CORS and request parsing

The goal of this project is to understand the complete data flow from client → server → database → client, and to practice building secure REST APIs.

Install Dependencies for Frontend & Backend

Frontend:

  npm install
  npm install react-router-dom react-toastify

Backend:

  npm install
  npm i express cors dotenv bcrypt body-parser joi jsonwebtoken mongoose

Environment Variables

• Create a .env file in the backend directory.
• Add the following variables with appropriate values

PORT = "-------- Any Port --------"

MONGO_CONN = "-------- Paste Your Mongo URI Here --------"

JWT_SECRET = "-------- Anything --------"