LexGen AI

An AI-powered legal contract generation and risk analysis platform. Generate legally structured contracts from plain language descriptions, then review clause-level risk insights before signing.

Features

• AI Contract Drafting - Describe your needs in plain language to generate professionally structured contracts
• Risk & Ambiguity Detection - Automatically flags risky, vague, or potentially unfavorable clauses
• Safer Alternatives - Provides recommended clause replacements with clear explanations
• RAG-Powered - Uses Retrieval-Augmented Generation with legal templates for better accuracy
• Interactive Q&A - Asks clarifying questions to ensure complete contracts

Tech Stack

Backend

• Node.js + Express + TypeScript
• MongoDB with Vector Search (Atlas)
• OpenAI GPT-4o-mini
• JWT authentication with HTTP-only cookies

Frontend

• Next.js 14 (App Router)
• React + TypeScript
• Tailwind CSS
• Framer Motion animations

Project Structure

Enigma2026/
├── Backend/
│   └── src/
│       ├── controllers/     # Request handlers
│       ├── services/        # Business logic (AI, documents, auth)
│       ├── Models/          # MongoDB schemas
│       ├── routes/          # API routes
│       ├── middlewares/     # Auth middleware
│       └── utils/           # Logger utilities
├── frontend/
│   ├── app/                 # Next.js pages
│   ├── components/          # React components
│   └── lib/                 # Utilities, API client, auth context
└── templates/               # Legal document templates for RAG

Setup

Prerequisites

• Node.js 20+
• pnpm
• MongoDB Atlas account
• OpenAI API key

Environment Variables

Backend (.env)

PORT=5000
MONGODB_URI=mongodb+srv://...
OPENAI_API_KEY=sk-...
JWT_SECRET=your-secret-key
CORS_ORIGIN=http://localhost:3000
TOP_K_RETRIEVAL=5

Frontend (.env.local)

NEXT_PUBLIC_API_URL=http://localhost:5000/api

Installation

# Backend
cd Backend
pnpm install
pnpm dev

# Frontend (new terminal)
cd frontend
pnpm install
pnpm dev

MongoDB Atlas Vector Index

Create a vector search index in Atlas for RAG functionality:

1. Go to MongoDB Atlas → Your Cluster → Atlas Search
2. Create Search Index → JSON Editor
3. Database: Enigma2026, Collection: templatechunks
4. Index Name: template_vector_index
5. Definition:

{
  "fields": [{
    "type": "vector",
    "path": "embedding",
    "numDimensions": 1536,
    "similarity": "cosine"
  }]
}

API Endpoints

Auth

• POST /api/auth/register - Create account
• POST /api/auth/login - Login
• POST /api/auth/logout - Logout
• GET /api/auth/me - Get current user

Documents

• GET /api/documents - List all documents
• POST /api/documents/create - Create new document
• POST /api/documents/generate - Generate contract
• POST /api/documents/analyze-risk - Analyze risks
• POST /api/documents/apply-suggestion - Apply risk fix
• POST /api/documents/apply-all-suggestions - Apply all fixes

Deployment

Production (Azure VM / VPS)

# Install dependencies
sudo apt update && sudo apt install -y nodejs nginx
npm install -g pnpm pm2

# Clone and setup
git clone <repo> && cd Enigma2026

# Backend
cd Backend && pnpm install
pm2 start "pnpm start" --name backend

# Frontend
cd ../frontend && pnpm install && pnpm build
pm2 start "pnpm start" --name frontend

# Nginx reverse proxy
sudo nano /etc/nginx/sites-available/lexgen
# Configure proxy_pass for / -> localhost:3000 and /api -> localhost:5000
sudo ln -s /etc/nginx/sites-available/lexgen /etc/nginx/sites-enabled/
sudo systemctl restart nginx

License

MIT

Usage

Generating a Contract

1. Register or log in via the frontend.
2. Navigate to the dashboard and select 'Create New Document'.
3. Describe your contract requirements in plain language.
4. Click 'Generate Contract' to receive a structured legal draft.

Analyzing Risks

1. After generating a contract, click 'Analyze Risks'.
2. The platform will highlight risky or ambiguous clauses.
3. Review flagged clauses and suggested safer alternatives.
4. Apply suggestions individually or all at once.

Downloading PDF

1. Once satisfied, click 'Download PDF' to export your contract.
2. Save or share the document as needed.

Example User Flow

• Create a consultancy agreement using a template.
• Analyze risks and apply safer clauses.
• Download the finalized contract for signing.