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JWT Generator Tool

Support for HMAC (HS256/HS384/HS512) and RSA (RS256/RS512) signing with auto key generation

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About JWT Generator Tool

The JWT Generator Tool is a free online utility that lets you easily and securely create JSON Web Tokens (JWT) directly in your browser. JWTs are a widely adopted token format used for Web API authentication and inter-service communication in microservice architectures.

Each token consists of three Base64URL-encoded parts—Header, Payload, and Signature—joined by dots.

Supported Signing Algorithms: - Symmetric signing (HMAC): HS256 (SHA-256), HS384 (SHA-384), HS512 (SHA-512) - Asymmetric signing (RSA): RS256 (RSA + SHA-256), RS512 (RSA + SHA-512) - Unsigned: none

You can conveniently enter standard JWT claims such as iss (issuer), sub (subject), aud (audience), exp (expiration time), iat (issued at), and nbf (not before) through the form interface, and add any custom claims in JSON format.

Convenient Key Generation Features: - Automatic HMAC secret generation (32 bytes for HS256, 48 bytes for HS384, 64 bytes for HS512) - Automatic RSA-2048 key pair generation (public and private keys in PEM format)

All signing operations use the browser's built-in Web Crypto API (SubtleCrypto), ensuring your secret keys and payload data are never transmitted to any external server. Whether you are testing API authentication during development, verifying OAuth 2.0 tokens, securing inter-service communication in microservices, or studying JWT structure for educational purposes, this tool provides a convenient and secure solution. The generated token is displayed with color-coded header, payload, and signature parts, making it easy to visually understand the JWT structure.

How to use JWT Generator Tool

  1. Select the signing algorithm: choose from HMAC (HS256 / HS384 / HS512) or RSA (RS256 / RS512). HS256 or RS256 or higher is recommended for security.
  2. Enter the payload. Set standard claims like iss (issuer), sub (subject), and exp (expiration) using the form fields, or write the payload directly in the JSON editor.
  3. For HMAC, enter a secret key; for RSA, enter the private key in PEM format. If you don't have a private key, use the 'Generate RSA-2048 Key Pair' button to auto-generate one.
  4. For HMAC algorithms like HS256, you can auto-generate cryptographically secure secrets using buttons like 'HS256 (32B)'.
  5. Click the 'Generate JWT' button to create a JWT token with color-coded header, payload, and signature parts.
  6. Click the generated token or use the 'Copy' button to copy it to your clipboard, then paste it into your API request's Authorization header.

Benefits of JWT Generator Tool

  • Works directly in your browser with no software installation required.
  • Your secret keys and payload data are never sent to any external server, ensuring complete security.
  • Supports both HMAC (HS256/HS384/HS512) and RSA (RS256/RS512) signing algorithms, suitable for a wide range of use cases.
  • Offers both form-based standard claim input and direct JSON editing, making it accessible for beginners and experts alike.
  • Built-in secret key and RSA key pair generation features help you maintain secure key management.
  • The generated token displays color-coded header, payload, and signature sections for easy JWT structure comprehension.

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