💰 Salary Calculator & Resume ATS Checker

A modern, Gen Z-friendly web application for calculating in-hand salary according to Indian tax laws and checking resume compatibility with Applicant Tracking Systems (ATS). Built with React/Vite frontend and NestJS backend.

✨ Features

💵 Salary Calculator

🧮 Calculate in-hand salary based on CTC and city
📍 Support for major Indian cities with accurate tax calculations
📊 Detailed salary breakdown (Basic, HRA, EPF, ESI, Professional Tax, Income Tax)
📈 Variable pay and insurance support
💾 Save calculation history in database
📜 User-specific calculation history with easy access

📄 Resume ATS Checker

🔍 Analyze resume compatibility with ATS systems
📝 Support for PDF and DOCX file formats (up to 2MB)
🎯 ATS score calculation (0-100)
✅ Keyword matching analysis
💪 Strengths identification
⚠️ Areas for improvement detection
💡 Actionable suggestions for optimization
⏱️ Rate limiting: 3 checks per user, resets every 12 hours

🔐 Authentication & User Management

🔑 GitHub OAuth integration
📧 Email/Password authentication
👤 User profile management
🔒 Secure JWT-based authentication
💾 User-specific data storage

🛠️ Tech Stack

Frontend

React 19
TypeScript
Vite
Lucide React (Icons)
Axios

Backend

NestJS
TypeScript
PostgreSQL
TypeORM
JWT Authentication
Passport.js (GitHub OAuth)
bcryptjs (Password hashing)
Multer (File uploads)
pdf-parse (PDF parsing)
mammoth (DOCX parsing)

🚀 Getting Started

Prerequisites

Node.js (v20.13.1 or higher)
PostgreSQL (v12 or higher) or Neon account
npm or pnpm
GitHub account (for OAuth, optional)

Installation

Clone the repository

git clone https://github.com/akashkaintura/salary-calculator.git
cd salary-calculator

Set up the Backend

cd backend
npm install

# Create a .env file
cp .env.example .env

# Edit .env with your configuration
# See Environment Variables section below

Set up Database

Option A: Using Neon (Recommended)

Go to neon.tech and create a project
Copy your DATABASE_URL connection string
Add it to backend/.env

Option B: Local PostgreSQL

createdb salary_calculator
# Or using psql
psql -U postgres
CREATE DATABASE salary_calculator;
\q

Seed the Database (Optional)

cd backend
npm run seed

Start the Backend

cd backend
npm run start:dev

The backend will run on http://localhost:3000

Set up the Frontend

cd frontend
npm install

# Create a .env file
echo "VITE_API_URL=http://localhost:3000" > .env

Start the Frontend

cd frontend
npm run dev

The frontend will run on http://localhost:5173

📝 Environment Variables

Backend (.env)

# Database Configuration
DATABASE_URL=postgresql://user:password@host:port/database?sslmode=require&channel_binding=require

# OR Use individual parameters (for local development)
# DB_HOST=localhost
# DB_PORT=5432
# DB_USERNAME=postgres
# DB_PASSWORD=your_password
# DB_NAME=salary_calculator

# Server Configuration
PORT=3000
NODE_ENV=development

# Frontend URL (for CORS)
FRONTEND_URL=http://localhost:5173

# GitHub OAuth (Get from https://github.com/settings/developers)
GITHUB_CLIENT_ID=your_github_client_id_here
GITHUB_CLIENT_SECRET=your_github_client_secret_here
GITHUB_CALLBACK_URL=http://localhost:3000/api/auth/github/callback

       # JWT Secret (Generate: openssl rand -base64 32)
       JWT_SECRET=your-super-secret-jwt-key-change-this-in-production

       # UPI Payment Configuration
       UPI_ID=your-upi-id@paytm  # Your UPI ID (e.g., yourname@paytm, yourname@ybl, etc.)
       MERCHANT_NAME=SalaryCalc   # Your business/merchant name
       PAYMENT_SECRET=your-payment-secret-key  # Secret key for payment verification (optional, auto-generated if not provided)
       ```

### Frontend (.env)

```env
VITE_API_URL=http://localhost:3000

🔐 Authentication Setup

GitHub OAuth Setup

Create GitHub OAuth App
- Go to GitHub Developer Settings
- Click "New OAuth App"
- Fill in:
  - Application name: Salary Calculator
  - Homepage URL: Your frontend URL
  - Authorization callback URL: Your backend URL + /api/auth/github/callback
- Click "Register application"
Get Credentials
- Copy Client ID
- Generate and copy Client Secret
- Add both to backend/.env

Email/Password Authentication

Users can register with email and password
No additional setup required
Passwords are securely hashed with bcrypt

🧮 Salary Calculation Logic

The calculator uses the following structure:

Basic Salary: 50% of Fixed CTC
HRA: 40% of Fixed CTC
Special Allowance: 10% of Fixed CTC
Fixed CTC: Total CTC - Variable Pay - Insurance
EPF: 12% of Basic Salary (employee contribution)
ESI: 0.75% of Gross Salary (if salary < ₹21,000)
Professional Tax: Varies by state/city
Income Tax: Based on new tax regime 2024-25

Variable Pay & Insurance

Variable Pay: Part of CTC but not included in monthly salary calculations
Insurance: Health/Life insurance premiums (part of CTC, not monthly salary)
Monthly salary is calculated from Fixed CTC only

📊 Resume ATS Checker Logic

The ATS checker analyzes resumes based on:

Keyword Matching: Checks for 50+ common ATS keywords
Resume Length: Optimal length analysis (300-1000 words)
Section Detection: Verifies presence of contact, experience, education, and skills sections
Action Verbs: Identifies use of action verbs
Score Calculation: Combines keyword density (60%) and length optimization (40%)

Rate Limiting

3 checks per user per 12-hour window
Automatic reset after 12 hours from first check
Usage tracking in database

🎯 API Endpoints

Authentication

POST /api/auth/register - Register with email/password
POST /api/auth/login - Login with email/password
GET /api/auth/github - Initiate GitHub OAuth
GET /api/auth/github/callback - GitHub OAuth callback
GET /api/auth/me - Get current user profile (requires auth)
POST /api/auth/update-profile - Update user profile (requires auth)

Salary Calculation

POST /api/salary/calculate - Calculate salary breakdown (requires auth)
GET /api/salary/history - Get user's calculation history (requires auth)

Resume ATS Checker

POST /api/ats/check - Upload and analyze resume (requires auth, file upload)
POST /api/ats/usage - Get remaining checks and reset time (requires auth)

📁 Project Structure

salary-calculator/
├── frontend/
│   ├── src/
│   │   ├── App.tsx              # Main application component
│   │   ├── App.css              # Styles
│   │   ├── main.tsx             # Entry point
│   │   ├── components/
│   │   │   ├── Login.tsx        # Login/Signup component
│   │   │   └── AtsChecker.tsx   # ATS Checker component
│   │   └── contexts/
│   │       └── AuthContext.tsx  # Authentication context
│   ├── package.json
│   └── vite.config.ts
├── backend/
│   ├── src/
│   │   ├── main.ts              # Application entry point
│   │   ├── app.module.ts        # Root module
│   │   ├── auth/                # Authentication module
│   │   │   ├── auth.controller.ts
│   │   │   ├── auth.service.ts
│   │   │   ├── strategies/      # GitHub & JWT strategies
│   │   │   └── dto/             # Register & Login DTOs
│   │   ├── user/                # User module
│   │   │   └── entities/
│   │   │       └── user.entity.ts
│   │   ├── salary/              # Salary calculation module
│   │   │   ├── salary.controller.ts
│   │   │   ├── salary.service.ts
│   │   │   ├── dto/
│   │   │   └── entities/
│   │   └── ats/                 # ATS checker module
│   │       ├── ats.controller.ts
│   │       ├── ats.service.ts
│   │       └── entities/
│   │           └── ats-usage.entity.ts
│   ├── package.json
│   └── tsconfig.json
└── README.md

🐛 Troubleshooting

Backend not connecting to database

Verify DATABASE_URL is correct
Check that database is active (not paused)
Ensure SSL is enabled if using cloud database

CORS errors

Ensure FRONTEND_URL in backend matches your frontend URL exactly
Check that frontend is using the correct VITE_API_URL

Authentication not working

Verify GitHub OAuth credentials are correct
Check that callback URL matches exactly
Ensure JWT_SECRET is set

File upload issues

Verify file is PDF or DOCX format
Check file size is under 2MB
Ensure user has remaining checks available

Build failures

Check Node.js version (should be 20+)
Verify all dependencies are in package.json
Check build logs for specific errors

📄 License

ISC

🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Name		Name	Last commit message	Last commit date
Latest commit History 165 Commits
backend		backend
frontend		frontend
.gitignore		.gitignore
README.md		README.md
TESTING.md		TESTING.md
bun.lock		bun.lock
docker-compose.yml		docker-compose.yml
package.json		package.json
push-to-github.sh		push-to-github.sh
railway.json		railway.json
render.yaml		render.yaml

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💰 Salary Calculator & Resume ATS Checker

✨ Features