What is a JWT Encoder?

A JWT Encoder is an online tool for creating and signing JSON Web Tokens. You can customize the Header (algorithm and type) and Payload (claims), then sign the token with a secret key to generate a complete JWT string.

What signing algorithms are supported?

This tool supports HMAC symmetric signing algorithms: HS256 (HMAC-SHA256), HS384 (HMAC-SHA384), and HS512 (HMAC-SHA512). These algorithms use a shared secret key for signing, suitable for most application scenarios.

Is my secret key safe?

Absolutely. All signing operations are performed locally in your browser using the Web Crypto API. Your secret key and token data are never uploaded to any server. We recommend closing the page after use to clear sensitive data.

What is the difference between JWT and JWS?

JWT (JSON Web Token) is the token format specification, while JWS (JSON Web Signature) is the signing mechanism. What we commonly call a JWT is actually a JWS — a signed JWT. There is also JWE (encrypted JWT). This tool generates JWS-format JWTs.

🔐 JWT Encoder

Create and Sign JWT Tokens · Custom Header / Payload · HS256/HS384/HS512

Signing Algorithm

Header (JSON)

Payload (JSON)

Secret Key

🎫 Generated JWT Token

📊 Token Info

❓ Frequently Asked Questions

Is JWT Encoder free to use?

Yes, JWT Encoder is completely free to use. No registration or login required — all features are available immediately.

Does JWT Encoder upload my data to a server?

No. JWT Encoder uses client-side processing — everything runs in your browser. Your data never leaves your device, and the tool works even without an internet connection.

Are there any usage limits for JWT Encoder?

JWT Encoder has no usage limits — it's free and unlimited. Since processing is done client-side, speed depends on your device. For very large files, we recommend processing in batches for the best experience.

Is my data safe when using JWT Encoder?

Absolutely. Everything runs locally: Signing Algorithm and Header are processed on your device, never sent to a server. No data is sent to any server, so there's zero risk of data leaks. Your information stays completely under your control.

Do I need to install any software?

No. JWT Encoder is a web-based tool — just open it in your browser and start using it. No downloads, plugins, or extensions required.

Can I use JWT Encoder on my phone?

Yes. JWT Encoder is fully responsive and works on phones, tablets, and desktops. The interface adapts automatically to your screen size.