Free Toolkit

JWT GeneratorGenerate signed JSON Web Tokens with custom claims, algorithm selection, and expiration.

JWT Generator illustration
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JWT Generator

Generate signed JSON Web Tokens with custom claims, algorithm selection, and expiration.

How to Use
1

Configure

Select algorithm and enter secret.

2

Add Claims

Edit JSON payload with custom claims.

3

Generate

Click Generate to create the signed JWT.

What Is JWT Generator?

This tool generates JWTs using HMAC signing (HS256, HS384, HS512) via the Web Crypto API. Customize the payload with any JSON claims, set expiration in hours, and sign with your secret key. The tool adds iat and exp claims automatically. JWTs are standard for stateless auth in modern apps, used in OAuth 2.0 and API authentication. Generated tokens follow RFC 7519. All crypto operations happen client-side using SubtleCrypto.

Why Use Our JWT Generator?

  • Supports HS256, HS384, HS512
  • Custom JSON payload with auto timestamps
  • Configurable expiration
  • 100% client-side — secrets never transmitted

Common Use Cases

API Testing

Generate test tokens for API auth.

Development

Create JWTs without backend.

Prototyping

Prototype auth flows with real JWTs.

Education

Learn JWT signing hands-on.

Technical Guide

JWT generation: (1) Create header with alg/typ, Base64URL-encode. (2) Create payload with claims, add iat/exp, Base64URL-encode. (3) Sign header.payload using HMAC with chosen hash via subtle.sign(). Final token is header.payload.signature. HS256 uses SHA-256. The secret is imported as an HMAC CryptoKey. Base64URL replaces +/ with -_ and strips padding.

Tips & Best Practices

  • 1
    Use strong random secrets
  • 2
    Set appropriate expiration
  • 3
    Never expose secrets in client code
  • 4
    Test with JWT Decoder

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Frequently Asked Questions

QFree?
Yes.
QSecret safe?
Yes, client-side.
QAlgorithms?
HS256, HS384, HS512.
QCustom claims?
Yes, any JSON.
QProduction-ready?
Yes, RFC 7519.

About JWT Generator

JWT Generator is a free online tool from FreeToolkit.ai. All processing happens directly in your browser — your data never leaves your device. No registration required. No ads. Just fast, reliable tools.