💰 Expense Tracker Web Application

A full-stack expense tracker built for students to manage income and expenses with authentication, charts, and monthly insights.

---

🚀 Features

• User registration & login
• Secure password hashing
• Role-based access control
• Add, edit, delete transactions (Full CRUD)
• Category-wise expense tracking
• Monthly filtering
• Interactive charts using Chart.js
• Responsive dashboard UI

---

🛠 Tech Stack

• Frontend: HTML, CSS, JavaScript
• Backend: PHP
• Database: MySQL
• Charts: Chart.js
• Auth: PHP Sessions + password_hash()

---

📊 Screenshots

🔐 Login Page

📝 Register Page

➕ Add Transaction Page

📈 Dashboard with Charts

✏️ Edit Transaction Page

📁 Check /Screenshots for more images

---

📂 Project Structure

ExpenseWebsite/
│
├── db.php
├── login.php
├── register.php
├── forgot_password.php
├── change_password.php
├── logout.php
├── index.php
├── dashboard.php
├── edit.php
├── style.css
├── login.css
└── README.md

---

▶ How to Run Locally

1. Install XAMPP
2. Start Apache & MySQL
3. Import database SQL
4. Place project in htdocs
5. Open http://localhost/ExpenseWebsite/login.php

---

🧠 Learning Outcomes

• CRUD operations
• SQL aggregation & filtering
• Session management
• Secure authentication
• Data visualization
• Responsive UI design

---

📌 Interview Highlight

“I built a secure expense tracking web application with authentication, full CRUD operations, monthly analytics, and interactive data visualization.”

---

🔐 PREPARED STATEMENTS (SECURITY UPGRADE)

❌ Old (unsafe)

$sql = "SELECT * FROM users WHERE username='$username'";

✅ New (SAFE)

$stmt = mysqli_prepare($conn,"SELECT * FROM users WHERE username=? LIMIT 1");

mysqli_stmt_bind_param($stmt, "s", $username);

mysqli_stmt_execute($stmt);

$result = mysqli_stmt_get_result($stmt);

$user = mysqli_fetch_assoc($result);

🔄 Example:

Insert Transaction (Secure)

$stmt = mysqli_prepare($conn,"INSERT INTO transactions (type, category, amount, description, created_at) VALUES (?, ?, ?, ?, ?)");

mysqli_stmt_bind_param($stmt,"ssdss",$type,$category,$amount,$description,$date);

mysqli_stmt_execute($stmt);