🛡️ JWT Inspector — VS Code Extension

A lightweight and developer-friendly extension to decode, validate, and inspect JSON Web Tokens (JWTs) directly inside VS Code — no external websites needed.

🚀 Features

🔍 1. Instant JWT Decode (No Internet Required)

• Automatically detects JWTs in your editor
• Decodes Header, Payload, and Signature in real-time
• Works offline — secure for sensitive tokens

🧩 2. Syntax-Highlighted JWT Panel

• Opens a side panel showing structured JSON
• Beautiful syntax highlighting for JSON keys, strings, numbers, and booleans
• Highlights expired tokens, missing claims, invalid structure, etc.

⏱️ 3. Expiry & Claim Validation

• Human-readable expiration status (e.g., "Expired 2 hours ago" or "Valid for 3 days")
• Highlights important claims:
  • exp - Expiration time
  • iat - Issued at
  • nbf - Not before
  • iss - Issuer
  • sub - Subject
  • aud - Audience
  • scope - Scope

🔐 4. Signature Algorithm Detection

• Displays algorithm used (HS256, RS256, ES256, etc.)
• Warns about insecure algorithms (e.g., none, deprecated ones)
• Visual badges for algorithm status

🧪 5. Token Integrity Checks

• Detect malformed tokens
• Detect mismatches between header alg and signature format
• Warn if payload isn't valid JSON
• Comprehensive error and warning messages

📋 6. Hover Preview

• Hover over any JWT string → see decoded header & payload instantly
• Quick preview without opening the panel

🔄 7. Copy-to-Clipboard Utilities

Quickly copy:

• Header JSON
• Payload JSON
• Pretty-printed JSON
• Individual claim values

🧰 8. Command Palette Support

Run with:

• JWT Inspector: Decode Token - Decode selected token
• JWT Inspector: Open Panel - Open the inspection panel

🗂️ 9. Supports Multiple Tokens in One File

• Auto-detect and lists all tokens found in the active editor
• Works with multiple tokens in the same document

📦 Installation

1. Open VS Code
2. Go to Extensions (Ctrl+Shift+X / Cmd+Shift+X)
3. Search for "JWT Inspector"
4. Click Install

Or install from the command line:

code --install-extension jwt-inspector

🎯 Usage

Method 1: Hover Preview

Simply hover your mouse over any JWT token in your editor to see a quick preview of the decoded header and payload.

Method 2: Command Palette

1. Select a JWT token in your editor
2. Press Ctrl+Shift+P (Windows/Linux) or Cmd+Shift+P (Mac)
3. Type "JWT Inspector: Decode Token"
4. Press Enter

Method 3: Right-Click Context Menu

1. Select a JWT token
2. Right-click and choose "JWT Inspector: Decode Token"

Method 4: Panel Input

1. Open the JWT Inspector panel using the command palette
2. Paste your JWT token into the input field
3. Click "Decode Token" or press Ctrl+Enter

🎨 Features in Detail

Modern UI

• Clean, intuitive interface with card-based layout
• Color-coded sections for easy navigation
• Responsive design that adapts to your VS Code theme
• Smooth animations and transitions

Smart Token Detection

• Automatically recognizes JWT tokens in your code
• Supports tokens in strings, comments, and configuration files
• Pattern matching for standard JWT format

Security

• All processing happens locally - no data leaves your machine
• No network requests required
• Safe for sensitive production tokens

🔧 Development

Building from Source

# Clone the repository
git clone https://github.com/kailashyogeshwar85/jwt-inspector.git
cd jwt-inspector

# Install dependencies
npm install

# Compile TypeScript
npm run compile

# Watch for changes
npm run watch

Running in Development Mode

1. Open the project in VS Code
2. Press F5 to launch a new Extension Development Host window
3. Test the extension in the new window

📝 Example JWT Token

Here's a sample JWT token you can use for testing:

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c

🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

📄 License

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

👤 Author

Kailash Yogeshwar

• Email: kailashyogeshwar85@gmail.com
• GitHub: @kailashyogeshwar85

🙏 Acknowledgments

• Built with VS Code Extension API
• Inspired by the need for secure, offline JWT inspection tools

⭐ If you find this extension useful, please consider giving it a star on GitHub!