🎙️ InterviewAI - AI-Powered Smart Interview Platform

InterviewAI is a modern, end-to-end mock interview platform that simulates realistic technical and HR interviews with interactive video avatars, speech synthesis, live speech-to-text recognition, and instant multi-metric AI evaluations.

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🌟 Highlights & Features

📄 1. Smart Resume Parsing & Customization

• Upload your resume in PDF format.
• Uses pdfjs-dist and AI extraction to identify your target role, years of experience, key projects, and skills.
• Tailors interview questions strictly around your actual background and chosen mode (Technical or HR).

🤖 2. Interactive Video Avatars & Voice Simulation

• Animated Interviewer Avatars: Switch seamlessly between female and male interviewer video personas.
• Speech Synthesis (TTS): Realistic audio playback of questions synchronized with interviewer video states.
• Voice Recognition (STT): Speak naturally into your microphone using the Web Speech API with real-time speech-to-text transcription.
• Manual Microphone Controls: Toggle mic recording anytime or review and edit transcribed responses before submitting.

⏱️ 3. Adaptive 5-Question Progression

• Progressive difficulty curve designed to test depth of knowledge:
  • Q1 – Q2: Easy (60 seconds)
  • Q3 – Q4: Medium (90 seconds)
  • Q5: Hard (120 seconds)
• Real-time countdown timer with automatic answer submission when time expires.

📊 4. Multi-Metric AI Scoring & Honest Feedback

• Every answer is evaluated on a 0 to 10 scale across three core competencies:
  • 🎯 Correctness: Accuracy, depth, and relevance to the question.
  • 🗣️ Communication: Clarity, phrasing, and articulation.
  • ⚡ Confidence: Delivery, poise, and structured thought.
• Concise, actionable feedback (10–15 words) just like a human interviewer.

📑 5. Analytics Scorecard & PDF Export

• Dynamic performance breakdown with interactive Recharts area charts and circular score rings.
• Download an official, formatted PDF Performance Report generated on-the-fly using jspdf and jspdf-autotable.

💳 6. Credit System & Razorpay Monetization

• New users receive 100 Free Credits on signup (each 5-question interview consumes 50 credits).
• Integrated Razorpay payment gateway with secure server-side HMAC-SHA256 signature verification.
  • Free Tier: 100 Credits (2 Full Interviews)
  • Starter Pack: ₹100 for 150 Credits
  • Pro Pack: ₹500 for 650 Credits (Best Value)

🔒 7. Secure Authentication

• Instant one-click Google OAuth powered by Firebase.
• HTTP-only JWT session cookies with secure same-site policies.

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🏗️ Architecture & Workflow

flowchart TD
    User([Candidate]) -->|Google Sign-In| Auth[Firebase Auth & JWT Session]
    User -->|Upload PDF Resume| Upload[Multer & pdfjs-dist Text Extraction]
    Upload -->|Extracted Profile + Role + Mode| AI_Gen[Groq LLM: openai/gpt-oss-120b]
    AI_Gen -->|Generates 5 Tailored Questions| Session[Interactive Interview Stage]
    
    subgraph Interview Stage
        Session -->|SpeechSynthesis| AudioOut[Interviewer Avatar Video & Voice]
        User -->|Microphone Voice Input| STT[Web Speech API Recognition]
        STT -->|Transcribed Answer + Timer Check| SubmitAnswer[Submit Answer]
    end
    
    SubmitAnswer -->|Evaluate Answer| AI_Eval[AI Metric Evaluation: Confidence, Communication, Correctness]
    AI_Eval -->|Save Feedback & Scores| DB[(MongoDB)]
    
    DB -->|All 5 Answered| Report[Performance Scorecard & Recharts Analytics]
    Report -->|Export Report| PDF[Downloadable PDF jsPDF]
    
    User -->|Recharge Credits| Razorpay[Razorpay Payment Gateway]
    Razorpay -->|HMAC Verification| Credits[Add User Credits]

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🛠️ Tech Stack

Frontend (/client)

• Framework: React 19 + Vite 7
• Styling: Tailwind CSS v4
• Animations: Motion (Framer Motion)
• State Management: Redux Toolkit (@reduxjs/toolkit, react-redux)
• Routing: React Router v7
• Data Visualization: Recharts & react-circular-progressbar
• PDF Generation: jsPDF & jspdf-autotable
• Auth & Icons: Firebase Auth, react-icons

Backend (/server)

• Runtime & Framework: Node.js (ES Modules) + Express 5
• Database: MongoDB via Mongoose 9
• AI Engine: Groq Cloud (openai/gpt-oss-120b)
• PDF Parsing: pdfjs-dist
• File Handling: multer
• Payments: razorpay Node SDK + Node.js crypto
• Security & Sessions: jsonwebtoken (JWT), cookie-parser, cors, dotenv

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📁 Repository Structure

InterviewAI/
├── client/                     # Frontend Vite + React application
│   ├── public/                 # Static assets
│   ├── src/
│   │   ├── assets/             # Images, icons, and interviewer avatar videos
│   │   │   ├── videos/         # male-ai.mp4, female-ai.mp4
│   │   │   └── ...
│   │   ├── components/         # Reusable React components
│   │   │   ├── AuthModel.jsx   # Google login dialog modal
│   │   │   ├── Footer.jsx      # Application footer
│   │   │   ├── Navbar.jsx      # Navigation bar with credits display
│   │   │   ├── Step1SetUp.jsx  # Resume upload & interview configuration
│   │   │   ├── Step2Interview.jsx # Active video/voice interview room
│   │   │   ├── Step3Report.jsx # Scorecard & PDF download view
│   │   │   └── Timer.jsx       # Per-question countdown timer
│   │   ├── pages/              # Primary route views
│   │   │   ├── Auth.jsx        # Authentication page
│   │   │   ├── Home.jsx        # Landing page with feature showcases
│   │   │   ├── InterviewHistory.jsx # Past interviews listing
│   │   │   ├── InterviewPage.jsx    # Orchestrator for Steps 1, 2, and 3
│   │   │   ├── InterviewReport.jsx  # Dedicated report permalink
│   │   │   └── Pricing.jsx          # Credit packages & Razorpay checkout
│   │   ├── redux/              # Redux slices and store configuration
│   │   ├── utils/              # Firebase initialization
│   │   ├── App.jsx             # Route definitions & user session bootstrapper
│   │   ├── main.jsx            # React root mount
│   │   └── index.css           # Global Tailwind imports
│   ├── .env.example            # Sample client environment variables
│   ├── package.json
│   └── vite.config.js
│
├── server/                     # Backend Express REST API
│   ├── config/
│   │   ├── connectDb.js        # MongoDB connection handler
│   │   └── token.js            # JWT signing helper
│   ├── controllers/
│   │   ├── auth.controller.js  # Google login & logout
│   │   ├── interview.controller.js # Resume parsing, Q-gen, scoring, reports
│   │   ├── payment.controller.js   # Razorpay order create & verify
│   │   └── user.controller.js  # Current user profile endpoint
│   ├── middlewares/
│   │   ├── isAuth.js           # JWT authentication guard
│   │   └── multer.js           # Disk storage for PDF resumes
│   ├── models/
│   │   ├── interview.model.js  # Interview schema with embedded questions
│   │   ├── payment.model.js    # Order & transaction records
│   │   └── user.model.js       # User account & credit balance
│   ├── routes/
│   │   ├── auth.route.js       # /api/auth
│   │   ├── interview.route.js  # /api/interview
│   │   ├── payment.route.js    # /api/payment
│   │   └── user.route.js       # /api/user
│   ├── services/
│   │   ├── openRouter.service.js # Groq AI chat completion client
│   │   └── razorpay.service.js   # Razorpay client instance
│   ├── index.js                # Express server entry point
│   ├── .env.example            # Sample server environment variables
│   └── package.json
│
├── .gitignore
└── README.md

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🔌 API Reference

🔐 Authentication (/api/auth)

Method	Endpoint	Description	Auth Required
POST	/api/auth/google	Sign in or register via Google credential, returns user and sets cookie	No
GET	/api/auth/logout	Clear session authentication cookie	No

👤 User (/api/user)

Method	Endpoint	Description	Auth Required
GET	/api/user/current-user	Fetch currently logged-in user profile & credits	Yes

🎯 Interview Operations (/api/interview)

Method	Endpoint	Description	Auth Required
POST	/api/interview/resume	Upload PDF resume (multipart/form-data) and extract skills/projects	Yes
POST	/api/interview/generate-questions	Generate 5 role-tailored questions (Costs 50 credits)	Yes
POST	/api/interview/submit-answer	Submit answer for evaluation (Scores correctness, confidence, communication)	Yes
POST	/api/interview/finish	Finalize interview and calculate weighted aggregate scores	Yes
GET	/api/interview/get-interview	List all historical interviews for current user	Yes
GET	/api/interview/report/:id	Fetch detailed report breakdown for a specific interview ID	Yes

💳 Payments (/api/payment)

Method	Endpoint	Description	Auth Required
POST	/api/payment/create-order	Create a Razorpay payment order for selected credit pack	Yes
POST	/api/payment/verify-payment	Verify HMAC-SHA256 signature and credit the user account	Yes

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🚀 Getting Started

Prerequisites

Make sure you have installed:

• Node.js (v18.x or higher)
• npm or pnpm / yarn
• MongoDB (local or MongoDB Atlas connection string)
• Accounts/Keys for:
  • Groq Console (API Key)
  • Razorpay Dashboard (Test Key & Secret)
  • Firebase Console (Google Authentication setup)

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1. Clone Repository

git clone https://github.com/your-username/InterviewAI.git
cd InterviewAI

2. Configure Backend (server)

Navigate to the server directory:

cd server
npm install

Create a .env file based on .env.example:

cp .env.example .env

Fill in your server credentials:

PORT=6000
MONGODB_URL=mongodb+srv://<username>:<password>@cluster0.mongodb.net/interviewai
JWT_SECRET=your_super_secret_jwt_key
GROQ_API_KEY=gsk_your_groq_api_key_here
RAZORPAY_KEY_ID=rzp_test_your_key_id
RAZORPAY_KEY_SECRET=your_razorpay_secret

Start the backend server:

npm run dev
# Server will listen on http://localhost:6000

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3. Configure Frontend (client)

Open a new terminal and navigate to the client directory:

cd client
npm install

Create a .env file based on .env.example:

cp .env.example .env

Fill in your frontend credentials:

VITE_FIREBASE_APIKEY=your_firebase_web_api_key
VITE_RAZORPAY_KEY_ID=rzp_test_your_key_id

Note on Backend URL: If running locally, check client/src/App.jsx and ensure ServerUrl points to http://localhost:6000 (or your active deployed backend URL).

Start the Vite development server:

npm run dev
# Application will run on http://localhost:5173

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⚙️ Environment Variables Summary

Server Environment (server/.env)

Variable	Description
PORT	Port number the backend server runs on (Default: 6000)
MONGODB_URL	MongoDB connection URI string
JWT_SECRET	Secret key used to sign and verify JWT authentication tokens
GROQ_API_KEY	Groq API key for LLM question generation & answer grading
RAZORPAY_KEY_ID	Razorpay Key ID for processing payments
RAZORPAY_KEY_SECRET	Razorpay Key Secret for cryptographic payment verification

Client Environment (client/.env)

Variable	Description
VITE_FIREBASE_APIKEY	Firebase API Key for Google OAuth authentication
VITE_RAZORPAY_KEY_ID	Razorpay Public Key ID passed to the checkout modal

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🛡️ License

This project is licensed under the ISC License. Feel free to fork, adapt, and build upon it!