JWT Sign

Sign JSON Web Tokens (JWT) with various algorithms including HMAC and RSA for secure authentication.

How It Works

1

Configure Token Payload

Enter your JWT header and payload data, including claims like user ID, expiration time, and custom fields.

2

Choose Signing Algorithm

Select the signing algorithm (HS256, RS256, etc.) and provide the appropriate secret key or private key.

3

Generate Signed JWT

The tool creates a cryptographically signed JWT token that you can use for authentication and authorization.

Frequently Asked Questions

What is a JWT and why sign it?

A JSON Web Token (JWT) is a secure way to transmit information between parties. Signing ensures the token hasn't been tampered with and verifies the issuer's identity.

Which signing algorithm should I use?

HS256 (HMAC) is simpler and uses a shared secret. RS256 (RSA) is more secure for distributed systems as it uses public/private key pairs. Choose based on your security requirements.

Is my secret key secure?

Yes, all JWT signing happens locally in your browser. Your secret keys and private keys never leave your device or get sent to any servers.

What claims should I include?

Common claims include 'sub' (subject/user ID), 'exp' (expiration time), 'iat' (issued at), and 'iss' (issuer). You can also add custom claims specific to your application.

How long should a JWT be valid?

JWT expiration depends on your use case. Short-lived tokens (15-30 minutes) are more secure, while longer-lived tokens (hours/days) are more convenient. Consider using refresh tokens for longer sessions.