JWT Generator

JWT Generator is a free browser-based tool to quickly create signed JSON Web Tokens. Simply enter your custom claims and secret or key, and this tool will generate a JWT instantly. No coding required, and your data never leaves your browser for maximum security.

Need to parse an existing token? Use the JWT Decoder and validator!

What is a JWT Generator?

A JWT generator is an online tool that creates JSON Web Tokens. It allows you to input token data (claims) and a secret or key, then outputs a signed JWT. This saves developers from writing code to manually generate tokens. To learn more about JSON Web Tokens(JWT) in more details, try our JWT Crash Course.

Supported Features:

• Support for all standard JWT claims.
• Custom claim support with dynamic field addition
• Flexible datetime input handling:
• Accepts
  • ISO 8601 datetime strings (e.g., “2025-12-31T23:59:59Z”)
  • Supports UNIX timestamps
• Automatic timestamp conversion and validation
• HMAC-SHA256 (HS256) algorithm based signature generation
• Ability to generate strong(32 chars) random secret key
• Copy-to-clipboard functionality
• Real-time error handling and feedback
• Default pre-filled values for quick JWT generation and testing
  

How To Use The JWT Generator:

1. Fill in the standard claims:
   • Issuer: The entity issuing the token (e.g., “my-app”)
   • Subject: The subject of the token (e.g., “user123”)
   • Audience: The intended recipient (e.g., “my-api”)
   • Expiration: When the token expires (e.g., “2025-12-31T23:59:59Z”)
   • Other standard claims as needed
2. Add custom claims (if required):
   • Click the “Add Claim” button
   • Enter the claim name and value
   • Add multiple custom claims as needed
3. Enter your signature key:
   • Provide a secure secret key for signing the JWT
4. Generate the JWT:
   • Click the “Build JWT” button
   • The generated JWT will appear in the output section
5. Copy the token:
   • Click the “Copy” icon on top right of the result token window to copy the token to the clipboard
   • Use the token in your application.

Standard JWT Claims:

JWT specifications supports the following standard claims, this generator tool supports all of them:

Error Handling & Validation

• Real-time validation of input fields
• Detailed error messages for:
  • Invalid JSON in custom claims
  • Missing required fields
  • Invalid datetime formats
  • Failed signature generation
• Secure error handling that never exposes sensitive data
• Graceful fallbacks for invalid inputs

Security/Privacy Considerations

• All cryptographic operations are performed using the standardized Web Crypto API
• No external dependencies are required for JWT generation
• Client-side only – no data is sent to any server
• The signature key is never stored or transmitted

Browser Compatibility

Compatible with modern browsers that support:

• Web Crypto API
• TextEncoder API
• Clipboard API
• ES6+ JavaScript features

Technical Details:

• Frontend: Pure HTML, CSS, and JavaScript
• Cryptography: Web Crypto API
  • HMAC-SHA256 for token signing
  • Secure key handling using SubtleCrypto
• Encoding:
  • Base64URL encoding for JWT components
  • UTF-8 encoding for string handling
• Input Processing:
  • DateTime parsing and validation
  • JSON structure validation
  • Chunk-based string processing for large tokens

Feedback

Please get in touch with us for any bug report/feature request/feedback.

JWT Generator FAQs (Frequently Asked Questions)