Interview Prep - MERN Stack Application

An AI-powered interview preparation platform built with the MERN (MongoDB, Express, React, Node.js) stack. This application helps users practice DSA problems, conduct mock interviews, and track their progress.

🚀 Features

• User Authentication: Secure login and registration system with JWT
• DSA Practice: Extensive collection of Data Structures and Algorithms problems
• Mock Interviews: AI-powered mock interview sessions with real-time feedback
• Progress Tracking: Track your progress across different topics and subjects
• Admin Dashboard: Manage problems, subjects, and topics
• Subject Management: Organize DSA problems by subjects and topics
• Performance Analytics: Visual charts and statistics of your progress

🛠️ Tech Stack

Frontend

• React (v19.2.0) - UI library
• Vite (v7.3.1) - Build tool and dev server
• TailwindCSS (v4.2.1) - Utility-first CSS framework
• React Router (v7.13.1) - Client-side routing
• Axios - HTTP client for API calls
• React Hook Form - Form state management
• Recharts - Data visualization library
• React Hot Toast - Notification system

Backend

• Node.js - Runtime environment
• Express (v5.2.1) - Web framework
• MongoDB (with Mongoose) - Database
• JWT - Authentication
• Groq SDK - AI integration for interview feedback
• ElevenLabs - Text-to-speech API
• OpenAI - Additional AI capabilities

📋 Prerequisites

• Node.js (v14 or higher)
• npm or yarn
• MongoDB (local or MongoDB Atlas)
• Git

🔧 Installation

1. Clone the Repository

git clone https://github.com/premngowda31-collab/Interview_prep.git
cd Interview_prep

2. Backend Setup

cd backend
npm install

Create a .env file in the backend folder with the following variables:

MONGO_URI=mongodb://127.0.0.1:27017/interview_prep
GROQ_API_KEY=your_groq_api_key
JWT_SECRET=your_secret_key
JWT_EXPIRES_IN=7d
PORT=5000
CLIENT_URL=http://localhost:5173
ELEVENLABS_API_KEY=your_elevenlabs_api_key
OPENAI_API_KEY=your_openai_api_key

3. Frontend Setup

cd frontend
npm install

🚀 Running the Application

Start Backend Server

cd backend
npm run dev

Backend will run on http://localhost:5000

Start Frontend Server

In a new terminal:

cd frontend
npm run dev

Frontend will run on http://localhost:5173

📁 Project Structure

Interview_Mern/
├── backend/
│   ├── config/          # Database configuration
│   ├── controllers/      # Route controllers
│   ├── middleware/       # Custom middleware
│   ├── models/          # Database schemas
│   ├── routes/          # API routes
│   ├── services/        # Business logic
│   ├── Server.js        # Main server file
│   └── .env             # Environment variables
│
├── frontend/
│   ├── src/
│   │   ├── components/  # Reusable components
│   │   ├── pages/       # Page components
│   │   ├── services/    # API service calls
│   │   ├── context/     # React context for state
│   │   ├── App.jsx      # Main app component
│   │   └── main.jsx     # Entry point
│   └── vite.config.js   # Vite configuration
│
└── README.md

🔌 API Endpoints

Authentication

• POST /api/auth/register - Register new user
• POST /api/auth/login - Login user
• GET /api/auth/me - Get current user
• PUT /api/auth/profile - Update user profile

DSA Problems

• GET /api/dsa/problems - Get all problems
• GET /api/dsa/problems/:id - Get problem details
• POST /api/dsa/problems/:id/solve - Mark problem as solved
• DELETE /api/dsa/problems/:id/solve - Unmark problem
• GET /api/dsa/companies - Get companies list
• GET /api/dsa/topics - Get topics list

Mock Interviews

• POST /api/interview/start - Start interview session
• GET /api/interview - Get all interviews
• GET /api/interview/:id - Get interview details
• PUT /api/interview/:id/answer/:qIdx - Submit answer
• PUT /api/interview/:id/complete - Complete interview
• GET /api/interview/:id/phase - Get current phase

Progress

• GET /api/progress - Get user progress

Admin (Protected)

• POST /api/admin/subjects - Create subject
• POST /api/admin/problems - Create problem
• PUT /api/admin/problems/:id - Update problem
• DELETE /api/admin/problems/:id - Delete problem

🔐 Authentication

The application uses JWT (JSON Web Tokens) for authentication. Tokens are stored in localStorage and sent with each request via the Authorization header.

🤖 AI Integration

The application uses:

• Groq API for fast AI responses in interviews
• OpenAI API for additional AI capabilities
• ElevenLabs for text-to-speech functionality

📊 Database Schema

User Model

• Email, password (hashed), name
• Role (user/admin)
• Profile information

Problem Model

• Title, description, difficulty
• Company tags, topics
• Solutions and examples

Interview Model

• Questions, answers
• Feedback from AI
• Performance metrics

Progress Model

• Solved problems count
• Topics covered
• Performance stats

🐛 Troubleshooting

MongoDB Connection Error

Ensure MongoDB is running locally or update MONGO_URI in .env to use MongoDB Atlas.

Port Already in Use

If ports 5000 or 5173 are in use, update the PORT in .env for backend or use npm run dev -- --port 3000 for frontend.

CORS Issues

Ensure CLIENT_URL in backend .env matches your frontend URL.

📝 Contributing

1. Fork the repository
2. Create a feature branch (git checkout -b feature/AmazingFeature)
3. Commit changes (git commit -m 'Add some AmazingFeature')
4. Push to branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

📄 License

This project is licensed under the ISC License.

👨‍💻 Authors

• Prem Ngowda - Initial work

🙏 Acknowledgments

• MongoDB for database solutions
• Groq for fast AI inference
• ElevenLabs for text-to-speech
• OpenAI for AI capabilities
• React ecosystem contributors

📞 Support

For support, email your-email@example.com or open an issue on GitHub.

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Happy Learning! 🎉