🎯 NexPrep AI

AI-Powered Mock Interview Platform with Intelligent Feedback & Resume Optimization

Features • Quick Start • Tech Stack • Documentation • Contributing

📖 Overview

NexPrep AI is a cutting-edge mock interview platform that leverages AI to simulate real-world interview scenarios. Get personalized feedback, optimize your resume for ATS systems, and build professional resumes—all in one place. Perfect for job seekers preparing for technical interviews, behavioral assessments, and career transitions.

Why This Platform?

Feature	Description
🎤 Real-Time Voice Interviews	Conduct natural voice-based interviews with AI using speech-to-text and synthesis technology
🤖 Smart Question Generation	AI generates tailored questions based on job role, experience level, and difficulty
📊 Actionable Feedback	Receive detailed performance metrics, ratings, and improvement suggestions after each interview
📄 ATS Resume Checker	Analyze your resume for ATS compatibility with rule-based scoring and AI insights
✏️ Professional Resume Builder	Create stunning resumes with 4 customizable templates (Modern, Professional, Creative, Executive)
🔐 Secure & Private	Firebase authentication with encrypted data storage in MongoDB

🚀 Quick Start

# Clone the repository
git clone https://github.com/yourusername/NexPrep-main.git
cd NexPrep-main

# Install dependencies
npm install

# Set up environment variables (see .env.local example below)
cp .env.example .env.local

# Run development server
npm run dev
# Visit http://localhost:3000

📚 For detailed setup instructions, see Installation Guide

🖼️ View Screenshots

✨ Features

🎤 Interview System

AI Mock Interviews
- Voice-based real-time interactions
- Customizable duration (15/30/45/60 min)
- Three difficulty levels (Easy/Medium/Hard)
- Webcam recording support
- Automatic question generation
Intelligent Feedback
- Detailed performance analytics
- Rating system (1-10 scale)
- Improvement suggestions
- Historical tracking

📊 Dashboard & Analytics

Interview history tracking
Performance metrics visualization
Questions solved counter
Average score calculations
Quick action cards

📄 Resume Tools

ATS Checker
- PDF & DOCX support
- Rule-based scoring (Structure, Impact, Skills)
- Missing sections detection
- Contact info validation
- Actionable recommendations
Resume Builder
- 4 professional templates
- Real-time preview
- Customizable sections
- Export-ready formats
- Template switching

🔐 User Management

Firebase email/password authentication
Secure session management
User-specific data isolation
Profile management

🛠 Tech Stack

Core Technologies

Backend & Database

AI & Integrations

📋 Complete Technology Breakdown

Frontend

Technology	Purpose	Version
Next.js	React framework with SSR/SSG	15.4.1
React	UI library	19.2.4
TypeScript	Type safety	5.8.3
Tailwind CSS	Utility-first styling	Latest
Framer Motion	Animations	12.23.9
Radix UI	Headless UI components	Latest
Lucide React	Icon library	0.525.0
React Webcam	Camera integration	7.2.0

Backend & Database

Technology	Purpose
MongoDB	NoSQL database
Mongoose	ODM for MongoDB
Firebase Auth	User authentication
Firebase Admin	Server-side Firebase SDK

AI & Processing

Technology	Purpose
Grok API (xAI)	Primary AI for question generation
Google Gemini AI	Alternative AI provider
react-speech-to-text	Voice input
Web Speech API	Text-to-speech synthesis

File Processing

Technology	Purpose
pdf-parse	PDF parsing
mammoth	DOCX parsing

DevOps & Deployment

Technology	Purpose
Vercel	Hosting & CI/CD
Turbopack	Fast bundler (dev)
ESLint	Code linting

🏗 Architecture

graph TB
    A[User Browser] -->|HTTPS| B[Next.js Frontend]
    B -->|Route Handlers| C[API Routes]
    C -->|Authentication| D[Firebase Auth]
    C -->|Data Queries| E[MongoDB]
    C -->|AI Requests| F[Grok API / Gemini AI]
    B -->|Real-time Voice| G[Web Speech API]
    B -->|File Upload| H[File Parser]
    H -->|PDF/DOCX| C
    E -->|Mongoose ODM| I[Data Models]
    
    style A fill:#61DAFB,stroke:#333,stroke-width:2px
    style B fill:#000000,stroke:#333,stroke-width:2px,color:#fff
    style D fill:#FFCA28,stroke:#333,stroke-width:2px
    style E fill:#47A248,stroke:#333,stroke-width:2px,color:#fff
    style F fill:#4285F4,stroke:#333,stroke-width:2px,color:#fff

Design Patterns

Pattern	Implementation	Purpose
Server Actions	`app/actions/*.js`	Server-side data mutations with Next.js 15
Component Composition	Radix UI + ShadCN	Reusable, accessible UI components
Singleton Pattern	`firebase/client.js`, `utils/mongodb.js`	Single database/auth instance
Factory Pattern	`utils/GeminiAIModal.js`	AI provider abstraction
MVC Architecture	Models (`utils/models.js`) + Controllers (Actions) + Views (Components)	Separation of concerns

📥 Installation

Prerequisites

Node.js >= 18.0.0
npm or yarn
MongoDB Atlas account (free tier available)
Firebase project
AI API Key (Grok/Gemini)

1️⃣ Clone Repository

git clone https://github.com/yourusername/NexPrep-main.git
cd NexPrep-main

2️⃣ Install Dependencies

npm install
# or
yarn install

3️⃣ Environment Configuration

Create a .env.local file in the root directory:

# MongoDB
MONGODB_URI=mongodb+srv://username:password@cluster.mongodb.net/nexprep
NEXT_PUBLIC_MONGODB_URI=mongodb+srv://username:password@cluster.mongodb.net/nexprep

# AI Provider (Choose one or both)
NEXT_PUBLIC_GROK_API_KEY=xai-xxxxxxxxxxxxxx
# OR
NEXT_PUBLIC_GEMINI_API_KEY=AIzaSyxxxxxxxxxxxxx

# Firebase Admin SDK (Server-side)
FIREBASE_PROJECT_ID=your-project-id
FIREBASE_CLIENT_EMAIL=firebase-adminsdk-xxxxx@your-project-id.iam.gserviceaccount.com
FIREBASE_PRIVATE_KEY="-----BEGIN PRIVATE KEY-----\nYourPrivateKey\n-----END PRIVATE KEY-----\n"

# Firebase Client (Public)
NEXT_PUBLIC_FIREBASE_API_KEY=AIzaSyxxxxxxxxxxxxx
NEXT_PUBLIC_FIREBASE_AUTH_DOMAIN=your-project-id.firebaseapp.com
NEXT_PUBLIC_FIREBASE_PROJECT_ID=your-project-id
NEXT_PUBLIC_FIREBASE_STORAGE_BUCKET=your-project-id.appspot.com
NEXT_PUBLIC_FIREBASE_MESSAGING_SENDER_ID=123456789012
NEXT_PUBLIC_FIREBASE_APP_ID=1:123456789012:web:abcdef123456

Where to get credentials:

🗄️ MongoDB: MongoDB Atlas
🤖 Grok API: xAI Console
🤖 Gemini AI: Google AI Studio
🔥 Firebase: Firebase Console → Project Settings → Service Accounts

4️⃣ Database Setup

# Optional: Seed demo data
node scripts/seed_demo_feedback.mjs

The MongoDB collections (mockinterviews, useranswers) will be created automatically on first run.

5️⃣ Run Development Server

npm run dev
# or
yarn dev

Open http://localhost:3000 in your browser.

🐳 Docker Setup (Alternative)

# Dockerfile
FROM node:18-alpine

WORKDIR /app

COPY package*.json ./
RUN npm install

COPY . .

RUN npm run build

EXPOSE 3000

CMD ["npm", "start"]

# Build and run
docker build -t nexprep-ai .
docker run -p 3000:3000 --env-file .env.local nexprep-ai

🔧 Common Installation Issues

Issue: Module not found: Can't resolve 'firebase'

# Solution: Reinstall dependencies
rm -rf node_modules package-lock.json
npm install

Issue: Firebase: Error (auth/invalid-api-key)

# Solution: Check that NEXT_PUBLIC_FIREBASE_API_KEY is correctly set
# Ensure no extra spaces or quotes in .env.local

Issue: MongooseServerSelectionError

# Solution: Whitelist your IP in MongoDB Atlas
# Network Access → Add IP Address → Allow Access from Anywhere (0.0.0.0/0)

Issue: Grok API Error: 401 Unauthorized

# Solution: Verify your API key
# Ensure NEXT_PUBLIC_GROK_API_KEY starts with 'xai-'

🎯 Usage

Interview Workflow

sequenceDiagram
    participant U as User
    participant D as Dashboard
    participant AI as AI Engine
    participant DB as Database
    participant V as Voice System

    U->>D: Create New Interview
    D->>AI: Generate Questions (Job Details)
    AI-->>D: Return Interview Questions
    D->>DB: Save Interview
    U->>V: Start Voice Interview
    V->>U: Ask Question (Speech Synthesis)
    U->>V: Answer (Speech-to-Text)
    V->>AI: Analyze Answer
    AI-->>V: Return Feedback & Rating
    V->>DB: Save User Answer
    U->>D: View Feedback Report

Step-by-Step Guide

1️⃣ Create Mock Interview

Navigate to Dashboard
Click "+ Add New Interview"
Fill in:
- Job Position (e.g., "Frontend Developer")
- Job Description (paste JD or key responsibilities)
- Years of Experience
- Location (optional)
- Duration (15/30/45/60 minutes)
- Difficulty (Easy/Medium/Hard)
Click "Start Interview"

2️⃣ Conduct Interview

Click "Start Recording" to enable webcam
Grant microphone & camera permissions
Click on each question to hear it read aloud
Speak your answer clearly
Click "Stop Recording" when done
Review your recorded answer
Click "Submit & Get Feedback"
View AI-generated feedback and ratings

3️⃣ Check ATS Score

Go to "ATS Checker" tab
Upload your resume (PDF/DOCX)
Review your score breakdown:
- Structure (15%)
- Impact (25%)
- Skills (30%)
- Style (20%)
- Brevity (10%)
Read detailed suggestions
Download optimized resume

4️⃣ Build Resume

Navigate to "Resume Builder"
Select a template
Fill in your details:
- Personal Info
- Professional Summary
- Experience
- Education
- Skills
- Projects
Preview in real-time
Export or print

Configuration Parameters

Parameter	Options	Description
Interview Duration	15, 30, 45, 60 min	Total interview time
Difficulty Level	Easy, Medium, Hard	Question complexity
Interview Mode	Voice, Text	Input method (Voice recommended)
Voice Language	en-US, en-GB, etc.	Speech synthesis language

⚙️ Advanced Configuration

Custom AI Prompts

Edit utils/GeminiAIModal.js to customize AI behavior:

export const chatSession = {
  sendMessage: async (inputPrompt) => {
    // Modify temperature (0.0 - 1.0)
    // Higher = more creative, Lower = more focused
    const response = await fetch("https://api.x.ai/v1/chat/completions", {
      body: JSON.stringify({
        model: "grok-beta",
        temperature: 0.7, // Adjust here
        // ... rest of config
      })
    });
  }
};

Database Schema Customization

Modify utils/models.js to add custom fields:

const MockInterviewSchema = new mongoose.Schema({
  // Add your custom fields
  customField: { type: String, maxlength: 500 },
  // ... existing fields
});

📂 Project Structure

NexPrep-main/
│
├── app/                          # Next.js App Router
│   ├── actions/                  # Server Actions
│   │   └── interview.js          # Interview CRUD operations
│   ├── auth/                     # Authentication pages
│   │   ├── sign-in/
│   │   └── sign-up/
│   ├── dashboard/                # Main application
│   │   ├── _components/          # Dashboard components
│   │   │   ├── AddNewInterview.jsx      # Interview creation modal
│   │   │   ├── InterviewList.jsx        # Interview history
│   │   │   └── Header.jsx               # Top navigation
│   │   ├── ats-checker/          # ATS resume analysis
│   │   │   └── _actions/
│   │   │       ├── analyze.js    # Rule-based ATS scoring
│   │   │       └── fileParser.js # PDF/DOCX parsing
│   │   ├── interview/
│   │   │   └── [interviewid]/
│   │   │       ├── start/        # Interview conduct page
│   │   │       └── feedback/     # Results & analytics
│   │   ├── questions/            # Question bank
│   │   ├── resume/               # Resume builder
│   │   │   └── _components/
│   │   │       └── templates/    # 4 resume templates
│   │   └── upgrade/              # Pricing (if applicable)
│   ├── globals.css               # Global styles
│   ├── layout.js                 # Root layout
│   └── page.js                   # Home (redirects to sign-in)
│
├── components/                   # Shared UI components
│   └── ui/                       # ShadCN UI components
│       ├── button.jsx
│       ├── dialog.jsx
│       ├── input.jsx
│       └── ...
│
├── firebase/                     # Firebase configuration
│   ├── admin.js                  # Server-side SDK
│   └── client.js                 # Client-side SDK
│
├── lib/
│   └── utils.js                  # Utility functions (cn helper)
│
├── public/                       # Static assets
│
├── scripts/                      # Database seeding scripts
│   ├── seed.mjs
│   ├── seed_feedback.mjs
│   └── seed_demo_feedback.mjs
│
├── utils/                        # Core utilities
│   ├── db.js                     # Database connection helper
│   ├── GeminiAIModal.js          # AI provider abstraction
│   ├── GeminiATS.js              # ATS AI analysis
│   ├── models.js                 # Mongoose schemas
│   ├── mongodb.js                # MongoDB singleton
│   └── schema.js                 # Validation schemas
│
├── .env.local                    # Environment variables (create this)
├── components.json               # ShadCN UI config
├── jsconfig.json                 # JavaScript config
├── next.config.mjs               # Next.js configuration
├── package.json                  # Dependencies
├── postcss.config.mjs            # PostCSS config
├── tailwind.config.js            # Tailwind CSS config
└── tsconfig.json                 # TypeScript config

🚀 Deployment

Vercel (Recommended)

Push your code to GitHub
Import project to Vercel
Add environment variables in Vercel dashboard
Deploy automatically

Environment Variables:

Go to Project Settings → Environment Variables
Add all variables from .env.local
Redeploy

Other Platforms

Netlify

npm run build

Add netlify.toml:

[build]
  command = "npm run build"
  publish = ".next"

[[plugins]]
  package = "@netlify/plugin-nextjs"

Docker + Cloud Run

# Build
docker build -t nexprep-ai .

# Tag
docker tag nexprep-ai gcr.io/YOUR_PROJECT/nexprep-ai

# Push
docker push gcr.io/YOUR_PROJECT/nexprep-ai

# Deploy to Cloud Run
gcloud run deploy nexprep-ai \
  --image gcr.io/YOUR_PROJECT/nexprep-ai \
  --platform managed \
  --region us-central1 \
  --allow-unauthenticated

Production Checklist

🧪 Testing

Run Tests

# Frontend tests
npm run test

# End-to-end tests (if configured)
npm run test:e2e

# Linting
npm run lint

Manual Testing Checklist

Authentication

Sign up with email/password
Sign in with existing account
Sign out functionality
Protected routes redirect to sign-in

Interview Flow

ATS Checker

Upload PDF resume
Upload DOCX resume
View ATS score breakdown
Download suggestions

Resume Builder

Switch between templates
Enter resume data
Preview updates in real-time
Export resume

📚 Documentation

Installation Guide
Usage Guide
API Reference (See Server Actions in app/actions/)
Contributing Guidelines
Troubleshooting

🗺 Roadmap

✅ Completed

AI-powered mock interviews with voice input
Real-time feedback and rating system
ATS resume checker with rule-based scoring
Resume builder with 4 templates
Firebase authentication
MongoDB data persistence
Dashboard analytics
Webcam recording support

🚧 In Progress

Multi-language support (i18n)
Advanced analytics dashboard with charts
Email notifications for interview reminders
Export interview transcripts to PDF
Mobile app (React Native)

📅 Planned

Want a feature? Open an issue or contribute!

🤝 Contributing

We welcome contributions! Follow these steps:

1️⃣ Fork the Repository

Click the Fork button at the top right of this page.

2️⃣ Clone Your Fork

git clone https://github.com/YOUR_USERNAME/NexPrep-main.git
cd NexPrep-main

3️⃣ Create a Feature Branch

git checkout -b feature/amazing-feature

4️⃣ Make Your Changes

Write clean, readable code
Follow existing code style
Add comments for complex logic
Test your changes locally

5️⃣ Commit Your Changes

git add .
git commit -m "feat: add amazing feature"

Commit Convention:

feat: New feature
fix: Bug fix
docs: Documentation changes
style: Code style changes (formatting)
refactor: Code refactoring
test: Adding tests
chore: Maintenance tasks

6️⃣ Push to Your Fork

git push origin feature/amazing-feature

7️⃣ Open a Pull Request

Go to the original repository
Click "New Pull Request"
Select your branch
Describe your changes clearly
Submit for review

Contribution Guidelines

Do ✅	Don't ❌
Write descriptive commit messages	Commit directly to `main`
Test your changes thoroughly	Submit untested code
Update documentation if needed	Introduce breaking changes without discussion
Follow existing code patterns	Ignore linting errors
Keep PRs focused and small	Bundle multiple unrelated changes
Be respectful in discussions	Use offensive language

Development Setup

# Install dependencies
npm install

# Run in development mode
npm run dev

# Build for production
npm run build

# Run production build locally
npm run start

# Lint code
npm run lint

💬 Support

Documentation: Read the Usage Guide
Issues: Report bugs or request features on GitHub Issues

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

Made with ❤️ by Ajinkya

🔗 Live Demo: https://nexprep-ai.vercel.app
🔗 Portfolio: https://itsajinkya.vercel.app
📫 LinkedIn: linkedin.com/in/ajinkya2004

⭐ Star this repo if you find it helpful!

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Name		Name	Last commit message	Last commit date
Latest commit History 4 Commits
app		app
components/ui		components/ui
firebase		firebase
lib		lib
public		public
scripts		scripts
utils		utils
.gitignore		.gitignore
README.md		README.md
components.json		components.json
jsconfig.json		jsconfig.json
next.config.mjs		next.config.mjs
package-lock.json		package-lock.json
package.json		package.json
postcss.config.mjs		postcss.config.mjs
tailwind.config.js		tailwind.config.js
tsconfig.json		tsconfig.json

Ajinkyaa2004/NexPrep

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🎯 NexPrep AI

AI-Powered Mock Interview Platform with Intelligent Feedback & Resume Optimization

📖 Overview

Why This Platform?

🚀 Quick Start

📑 Table of Contents

✨ Features

🎤 Interview System

📊 Dashboard & Analytics

📄 Resume Tools

🔐 User Management

🛠 Tech Stack

Core Technologies

Backend & Database

AI & Integrations

Frontend

Backend & Database

AI & Processing

File Processing

DevOps & Deployment

🏗 Architecture

Design Patterns

📥 Installation

Prerequisites

1️⃣ Clone Repository

2️⃣ Install Dependencies

3️⃣ Environment Configuration

4️⃣ Database Setup

5️⃣ Run Development Server

🎯 Usage

Interview Workflow

Step-by-Step Guide

1️⃣ Create Mock Interview

2️⃣ Conduct Interview

3️⃣ Check ATS Score

4️⃣ Build Resume

Configuration Parameters

Custom AI Prompts

Database Schema Customization

📂 Project Structure

🚀 Deployment

Vercel (Recommended)

Other Platforms

Production Checklist

🧪 Testing

Run Tests

Manual Testing Checklist

📚 Documentation

🗺 Roadmap

✅ Completed

🚧 In Progress

📅 Planned

🤝 Contributing

1️⃣ Fork the Repository

2️⃣ Clone Your Fork

3️⃣ Create a Feature Branch

4️⃣ Make Your Changes

5️⃣ Commit Your Changes

6️⃣ Push to Your Fork

7️⃣ Open a Pull Request

Contribution Guidelines

Development Setup

💬 Support

📄 License

Made with ❤️ by Ajinkya

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