Bank Account Application

A simple bank account application with Express backend and vanilla JavaScript frontend.

Features

• User account management with unique user IDs
• Deposit and withdrawal functionality
• Transaction history
• Balance tracking
• Input validation
• Error handling
• Responsive UI

Setup

1. Install dependencies:

npm install

2. Start the server:

npm start

3. Open your browser and navigate to:

http://localhost:3000

Technical Details

• Backend: Express.js
• Frontend: Vanilla JavaScript, HTML, CSS
• Data Storage: In-memory (Map object)
• API Endpoints:
  • GET /api/balance?userId={userId} - Get account balance and transactions
  • POST /api/balance - Process transaction (deposit/withdrawal)

Notes

• Data is stored in memory and will be lost when the server restarts
• Each user can have up to 10 most recent transactions
• Withdrawals are prevented if the amount exceeds the current balance