Build a basic version of PayTM

Bank Account Management API

This project provides a RESTful API for managing bank account balances and transferring money between accounts. The API is built using Node.js, Express, and MongoDB with Mongoose.

Table of Contents

• Installation
• Usage
• API Endpoints
  • User Signup
  • User Signin
  • Get Balance
  • Transfer Money
• Middleware
• Database Schema
• Error Handling

Installation

1. Clone the repository:

   git clone https://github.com/yourusername/bank-account-management-api.git

2. Navigate to the project directory:

   cd /backend

3. Install dependencies:

   npm install

4. Create a .env file in the root directory and add your environment variables:

   PORT=3000
   SERVER_KEY1=your_jwt_secret_key
   MONGODB_URI=your_mongodb_connection_string

5. Start the server:

   npm start

Usage

Use the following base URL to access the API:

API Endpoints

User Signup

• URL: /api/v1/user/signup
• Method: POST
• Body:

  {
    "firstname": "John",
    "lastname": "Doe",
    "username": "john.doe@example.com",
    "password": "your_password"
  }

• Response:

  {
    "err": false,
    "message": "User created successfully"
  }

User Signin

• URL: /api/v1/user/signin
• Method: POST
• Body:

  {
    "username": "john.doe@example.com",
    "password": "your_password"
  }

• Response:

  {
    "err": false,
    "msg": "LOGIN SUCCESSFUL",
    "token": "your_jwt_token"
  }

Get Balance

• URL: /api/v1/user/balance
• Method: GET
• Headers:

  Authorization: Bearer your_jwt_token

• Response:

  {
    "err": false,
    "balance": 1000
  }

Transfer Money

• URL: /api/v1/user/transfer
• Method: POST
• Headers:

  Authorization: Bearer your_jwt_token

• Body:

  {
    "amount": 100,
    "to": "recipient_user_id"
  }

• Response:

  {
    "message": "Transfer successful"
  }

Middleware

//import jwt
const jwt = require("jsonwebtoken");
//middleware
const authMiddleware = (req, res, next) => {
  const authHeader = req.headers.authorization;

  if (!authHeader) {
    return res.status(403).json({ err: true, msg: "No token provided" });
  }

  const token = authHeader.split(" ")[1];
  console.log("Received token:", token);
  //verify server keY
  try {
    const decoded = jwt.verify(token, process.env.YOUR_KEY_HERE);

    req.user = decoded;

    next(); //PASSING ROUTE NEXT ROUTE
  } catch (err) {
    console.error("JWT verification error:", err);
    return res.status(403).json({ err: true, msg: "Invalid token" });
  }
};

Authentication Middleware

The authMiddleware function is used to protect routes that require authentication. It verifies the JWT token and attaches the user information to the request object.

Database Schema

User Schema

Account Schema

//user
const UserSchema = new mongoose.Schema({
  firstname: String,
  lastname: String,
  username: { type: String, unique: true },
  password: String,
});

//account
const Bankschema = new mongoose.Schema({
  userID: { type: mongoose.Schema.Types.ObjectId, ref: "User", required: true },
  Balance: { type: Number, required: true },
});