YouTube Transcript Extractor

Grabs text from YouTube videos (including unlisted ones and auto-generated captions). Works automatically or on-demand.

Quick Start

Install in 6 steps:

1. Get the code: Click green "Code" button → "Download ZIP"
2. Extract: Unzip to a folder somewhere on your computer
3. Open Chrome extensions: Go to chrome://extensions/
4. Enable developer mode: Toggle "Developer mode" (top right)
5. Load extension: Click "Load unpacked" → select your extracted folder
6. Done. Works immediately on YouTube.

Note: Use the extracted folder, not the ZIP file (obviously)

How It Works

Technical Method

This extension intercepts YouTube's internal caption requests with JavaScript:

The mechanics: Overrides XMLHttpRequest and fetch to monitor YouTube's network calls. When YouTube hits /api/timedtext (their caption API), the extension grabs a copy of the response and processes it locally.

What actually happens:

1. Extension injects monitoring code into YouTube pages
2. YouTube requests captions → extension copies the request
3. YouTube gets caption data → extension processes the same data
4. Extension converts YouTube's format to clean text
5. Stores result in your browser (Chrome's local storage)
6. You access it through the popup

No external servers involved. Just local JavaScript doing its thing based on what YouTube already loads in your browser.

What It Does

Automatic Capture

• Grabs transcripts when you turn on captions (CC button)
• Shows browser notification when ready
• Badge appears on extension icon

Manual Extract

• Click extension icon on any YouTube page
• Pick language if multiple options available
• Get clean text

Export Options

• Copy to clipboard
• Download individual transcripts in multiple formats (TXT, JSON, Markdown)
• Download all captured transcripts in bulk
• Plain text or timestamped format
• Includes video metadata (title, language, word count, timestamps)

Transcript Management

• View list of all captured transcripts
• Access previously captured transcripts from current session
• Clear individual transcripts or all at once
• Transcripts stored in session (cleared on browser restart)

How to Use

Method 1: Auto-Capture (Easiest)

1. Go to any YouTube video
2. Turn on captions (CC button)
3. Wait for notification
4. Click extension icon to see transcript

Method 2: Manual Extract

1. Go to YouTube video
2. Click extension icon
3. Pick language if needed
4. Copy or download

What You Get

The extension creates clean, formatted text files with:

• Video title and ID
• Language and caption type (manual vs auto-generated)
• Word count
• Timestamp of when you extracted it
• Option for timestamps (MM:SS format)

Example filename: youtube_transcript_How_to_Learn_Programming_abc123xyz.txt

Supported Videos

✅ Works with:

• Public videos with captions
• Unlisted videos you have access to
• Auto-generated captions
• Multiple languages (when available)
• Live streams with captions

❌ Does not work with:

• Private videos
• Videos without any captions
• Copyright-protected content without captions

Browser Support

Requires Chrome or Chromium-based browsers (Edge, Brave, Opera). Uses modern web features that need Manifest V3 support.

Permissions Explained

This extension needs permission to:

• YouTube access: Read video information and captions
• Storage: Save transcripts temporarily
• Notifications: Alert you when auto-capture works
• Active tab: Know which YouTube video you're watching

No data is sent to external servers. Everything stays in your browser.

Troubleshooting

Extension icon shows no badge

• Make sure captions (CC) are enabled on the video
• Try refreshing the YouTube page
• Check that the video actually has captions available

"No transcripts available" message

• Verify the video has captions (look for CC button)
• Try selecting a different language if multiple are available
• Some videos may have restricted caption access

Copied text looks messy

• Choose the "Plain text" option instead of timestamped
• The text includes automatic cleanup of HTML formatting

Advanced Features

Click to see technical details

How It Works Behind the Scenes

The extension uses three main components:

• Background script: Stores transcripts and shows notifications
• Content script: Reads YouTube page information
• Page injection: Captures YouTube's internal caption requests

Caption Format Support

• JSON3: Modern YouTube format (preferred)
• XML: Legacy format (automatic fallback)
• Multiple languages: Supports all YouTube-available languages

Storage Strategy

Transcripts are stored in session storage:

• Available during current browser session
• Cleared when browser is closed/restarted
• Multiple transcripts can be captured and managed
• No persistent storage across browser sessions

Your data never leaves your device.

File Structure Reference

For developers: Extension architecture

manifest.json          → Extension configuration
├── background.js      → Handles storage and notifications
├── content.js         → Interacts with YouTube pages
├── inject.js          → Captures YouTube's caption API calls
├── popup.html/js/css  → Extension interface
└── icons/             → Extension icons

Component Communication:

• Extension popup ↔ Content script (video info requests)
• Content script ↔ Background script (transcript storage)
• Injected script → Content script (captured transcript data)

Technical Implementation:

• Intercepts YouTube's /api/timedtext requests
• Parses both modern (JSON3) and legacy (XML) caption formats
• Uses Chrome's Manifest V3 service worker architecture
• Handles YouTube's single-page application navigation