JWT Generator

About JWT Generator

JWT Generator is a tool to create JSON Web Tokens (JWT) based on the HS256 algorithm. JWT is a compact, URL-safe token format commonly used for authentication and authorization in modern web applications. This tool allows you to quickly generate JWT tokens for testing and development purposes without writing any code.

How It Works

A JWT consists of three parts: Header (algorithm and token type), Payload (claims/data), and Signature (created by signing the header and payload with a secret key). This tool uses the HS256 (HMAC with SHA-256) algorithm to generate the signature. All processing happens entirely in your browser - no data is sent to any server, ensuring complete privacy and security.

Use Cases

• API Testing: Generate tokens to test protected API endpoints in tools like Postman, Insomnia, or curl. Perfect for testing authentication headers and authorization flows.
• Local Development: Create mock tokens when the backend authentication system is not yet fully implemented. Helps frontend developers work independently without waiting for backend completion.
• Debugging Roles & Permissions: Test how your application behaves with different payload values such as user roles, permissions, feature flags, or custom claims.
• QA & Testing: Testers can generate tokens with various payloads to simulate different user scenarios and edge cases without accessing production systems.
• Learning & Education: Understand how JWT works by experimenting with different header, payload, and secret combinations. See how changes affect the resulting token structure.

How to Use

1. Enter your payload data in JSON format (user info, roles, claims, etc.)
2. Optionally modify the header if needed (defaults to HS256)
3. Enter a secret key (minimum 8 characters) - use a test key, never production secrets
4. Click 'Generate Token' to create your JWT
5. Copy the generated token and use it in your API client or application

Important Notes

• This tool runs 100% in your browser. No tokens or secrets are stored or transmitted to any server.
• Only supports HS256 (HMAC SHA-256) algorithm. For other algorithms (RS256, ES256), use appropriate backend tools.
• This tool generates tokens but does not verify them. Use JWT Decoder to inspect existing tokens.
• For development and testing only. Never use production secrets or generate tokens for production use.