JWT Generator – Create & Sign JWT Tokens Online
Generate custom JWT tokens for development and testing. Choose algorithms, set claims, and get instant signed tokens—securely in your browser.
JWT Token Generator
What is a JWT Generator?
A JWT Generator lets you create custom JSON Web Tokens for use in development, testing, and learning. You can specify the header, payload, algorithm, and secret or key.
How does it work?
- Choose your signing algorithm (HS256, RS256, etc.).
- Enter your desired claims and payload data.
- Optionally set expiration, audience, and other standard claims.
- Generate a signed JWT instantly, ready for use in your app or API.
JWT Fundamentals
- What is a JWT? A compact, URL-safe token format for securely transmitting information between parties as a JSON object.
- JWT Structure: Consists of a header, payload, and signature. Each part is Base64URL encoded and separated by dots.
- Security Best Practices: Always use strong secrets/keys, set short expirations, and avoid sensitive data in payloads.
- Common Claims:
iss(issuer),sub(subject),aud(audience),exp(expiration),nbf(not before),iat(issued at),jti(JWT ID). - JWT vs Other Tokens: JWTs are stateless and self-contained, unlike session tokens or API keys.
- Troubleshooting: Use this tool to generate tokens for debugging authentication, authorization, and integration flows.
Frequently Asked Questions
Are the JWTs generated here secure for production use?
The JWTs generated use standard algorithms and are cryptographically sound, but you should NEVER use tokens generated on any online tool in production. Generate production tokens server-side with your own secure keys. Use our tool only for testing, learning, and development.
What's the difference between HS256 and RS256 algorithms?
HS256 uses a shared secret (symmetric) - the same key signs and verifies tokens. RS256 uses public/private key pairs (asymmetric) - private key signs, public key verifies. RS256 is better for distributed systems where multiple services need to verify tokens without sharing secrets.
How do I set the expiration time correctly?
Expiration ('exp') should be a Unix timestamp (seconds since Jan 1, 1970). For example, to expire in 1 hour, use: Math.floor(Date.now() / 1000) + 3600. Our tool provides helpers to set common expiration times like 1 hour, 1 day, or 1 week.
Can I generate tokens without signatures (alg: 'none')?
Yes, but this is highly discouraged for any real use. Unsigned tokens (alg: 'none') offer no security and can be easily forged. Use them only for testing scenarios where security isn't a concern. Always use proper signing algorithms in production.
What claims should I include in my JWT?
Include standard claims like 'iss' (issuer), 'sub' (subject/user ID), 'aud' (audience), 'exp' (expiration), and 'iat' (issued at). Add custom claims for your application needs, but avoid sensitive data. Keep payloads minimal for better performance.