AI based Legal Highlighter: A Smart GenAI Chrome Extension for Understanding Legal Terms Instantly

Understanding legal documents, online judgments, contracts, or news articles can be overwhelming for non-lawyers and even for tech professionals. Legal terminology is dense, context-sensitive, and often buried inside long paragraphs. To solve this real-world problem, I developed a GenAI-powered Chrome extension called the AI based Legal Highlighter.

This tool automatically detects legal terms on any webpage and provides instant, AI-generated explanations using a multi-layered intelligence system. Whether you are a student, developer, journalist, entrepreneur, or simply someone trying to understand legal content better, this extension bridges the gap between legal language and everyday understanding.

This article explains what the AI based Legal Highlighter is, how it works internally, how to install it, and why it stands out among existing tools.

Published by TechToGeek.com

What Is AI based Legal Highlighter?

AI based Legal Highlighter is a Chrome extension built using Generative AI that scans webpages in real time, identifies legal terms, highlights them visually, and shows contextual definitions on hover.

Unlike simple keyword-based tools, this extension uses a smart fallback mechanism powered by OpenAI and Tavily, ensuring that even rare or jurisdiction-specific terms (like IPC sections) are explained accurately.

Key Capabilities at a Glance

Automatic detection of legal terms such as:
- IPC sections (IPC 420, IPC 302)
- Sections (Section 21, Section 302)
- Articles, statutes, and common legal phrases
Multi-tier definition lookup system
AI-generated legal explanations
Lightweight, fast, and privacy-conscious
Works on any website

Why I Built This Tool

Most legal content on the internet assumes prior legal knowledge. Even simple terms like indemnity, force majeure, or Section 302 can be confusing without context.

Existing solutions often fail because:

They rely only on static dictionaries
They do not understand legal context
They are limited to specific websites

The AI based Legal Highlighter was designed to:

Work universally
Adapt to different legal terminologies
Provide human-readable explanations instantly

Core Features of AI based Legal Highlighter

1. Automatic Legal Term Detection

The extension scans the webpage’s text nodes and identifies legal terms using:

Pattern-based detection (IPC, Sections, Articles)
A curated local legal dictionary

Detected terms are visually highlighted, making them easy to spot while reading.

2. Intelligent Multi-Tier Lookup System

This is where the extension truly shines.

When a legal term is detected, the extension follows this flow:

Local Legal Database
Dictionary API + OpenAI Evaluation
Tavily Web Search
AI Synthesis using OpenAI

This ensures both speed and accuracy.

3. Interactive Tooltips

Hovering over a highlighted term displays:

The term
A concise legal explanation
The source (Local / AI / Web Search)

No page reloads. No popups. Just instant clarity.

4. Developer-Friendly Debug Logs

For transparency and debugging, the extension logs:

Detected terms
Lookup stages
API fallbacks

This makes it ideal for developers and contributors.

Installation Guide (Step-by-Step)

Step 1: Get Required API Keys

You need two API keys.

OpenAI API Key

Visit: https://platform.openai.com/api-keys
Create an API key
Copy the key (starts with sk-)

Tavily API Key

Visit: https://tavily.com
Sign up for a free account
Generate your API key (starts with tvly-)

Step 2: Install the Chrome Extension

Download or clone the repository: https://github.com/subasen85/legal-highligter-ai.git
Open Chrome and navigate to: chrome://extensions
Enable Developer Mode (top-right corner)
Click Load unpacked
Select the project folder containing:
- manifest.json
- content.js
- background.js

Step 3: Configure API Keys

Click the extension icon in the Chrome toolbar
Enter:
- OpenAI API Key
- Tavily API Key
Click Save API Keys
You should see:
“API keys saved successfully!”

Your extension is now ready.

How It Works (Technical Deep Dive)

Architecture Overview

The extension follows Chrome’s Manifest V3 architecture:

content.js – Scans and highlights webpage text
background.js – Handles API calls and AI logic
popup.html / popup.js – Stores API keys securely
legal-terms.json – Local legal dictionary

Step-by-Step Definition Flow

1. Page Scanning (content.js)

const legalPatterns = [
  /\bIPC\s*\d+[A-Z]?\b/gi,
  /\bSection\s*\d+[A-Z]?\b/gi,
  /\bArticle\s*\d+[A-Z]?\b/gi
];

The extension scans text nodes and highlights matches dynamically.

2. Local Database Check

if (legalTermsData.terms[cleanWord]) {
  return legalTermsData.terms[cleanWord];
}

If the term exists locally, the definition is returned instantly.

3. Background Service Lookup

If not found locally, the request is sent to background.js:

chrome.runtime.sendMessage({
  action: 'getDefinition',
  term: cleanWord
});

4. Dictionary + OpenAI Evaluation

const aiResponse = await fetch('https://api.openai.com/v1/chat/completions', {
  method: 'POST',
  headers: {
    'Authorization': `Bearer ${openaiKey}`
  }
});

OpenAI selects the most legally relevant meaning from dictionary results.

5. Tavily Web Search Fallback

For terms like IPC420:

fetch('https://api.tavily.com/search', {
  method: 'POST',
  body: JSON.stringify({
    query: `legal definition of ${term}`
  })
});

Results are synthesized using OpenAI to generate a clean definition.

Example: IPC Section Detection

When the extension encounters:

“He was charged under IPC421 and Section 302”

The system responds with:

IPC421 → Explained via Tavily + AI
Section 302→ Recognized as murder under IPC

All without page reload or manual search.

Privacy & Security Considerations

API keys are stored using chrome.storage.sync
No browsing data is collected or stored
Only detected legal terms are processed
API calls are minimal and cached

Who Can Benefit from AI based Legal Highlighter?

Law students
Journalists covering legal news
Developers reading compliance docs
Startup founders reviewing contracts
Anyone confused by legal jargon

Frequently Asked Questions (FAQ)

1. Is AI based Legal Highlighter free to use?

Yes, the extension is free. API usage depends on OpenAI and Tavily free tiers.

2. Does it work on Indian legal terms?

Yes. It supports IPC sections, Articles, and Indian legal terminology.

3. Are my API keys safe?

Yes. Keys are stored locally in Chrome’s secure storage.

4. Can I add my own legal terms?

Absolutely. You can extend legal-terms.json with custom terms.

5. Does it slow down browsing?

No. The extension is lightweight and optimized.

Final Thoughts

The AI based Legal Highlighter demonstrates how Generative AI can solve real usability problems in everyday browsing. By combining static knowledge, AI reasoning, and web intelligence, this tool makes legal content accessible to everyone.

If this project resonates with you, explore the code, share feedback, or collaborate through the Contact Us page of TechToGeek.com.