JWT Signer — Free Online Tool
Create and sign JSON Web Tokens using HMAC-SHA256, HS384, or HS512. Define the JSON payload, enter a secret key, and generate a signed JWT. All signing happens in your browser using the SubtleCrypto API.
100% client-side. No uploads. Your data never leaves your browser.
How to use JWT Signer
- Enter your secret key.
- Edit the JSON payload.
- Choose algorithm and expiry.
- Click Sign to generate the JWT.
Frequently Asked Questions
Is this suitable for production?
For testing and development only. Production JWT signing should happen server-side with properly managed secrets.
What algorithms are supported?
HMAC-based: HS256 (SHA-256), HS384 (SHA-384), HS512 (SHA-512). RSA/ECDSA are not supported.
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