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JWT Builder / Generator

Create and sign JSON Web Tokens with HMAC (HS256, HS384, HS512). Set payload claims, expiry, and secret key. Signed in your browser using the Web Crypto API — no server, no tracking.

Developer Tools Runs locally No data sent
jwt hmac hs256 authentication client-side only
Header
Signing Secret
Payload Claims
Key Value
Generated Token
Fill in the fields above to generate a token—
● Header ● Payload ● Signature
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Signing uses the browser's native Web Crypto API —your secret never leaves the page. HMAC tokens can be verified by any JWT library using the same secret. Use the JWT Decoder to inspect the generated token or paste tokens from your app.

What is JWT Builder?

JWT Builder creates signed JSON Web Tokens in the browser using HMAC algorithms such as HS256, HS384, and HS512. It is useful for generating sample tokens, testing claim sets, and validating how your application handles roles, expiry, and custom payload fields.

How to Use JWT Builder

  1. Choose the HMAC algorithm you want to use.
  2. Enter or edit the payload claims you need in the token.
  3. Provide the signing secret and build the token.
  4. Copy the generated JWT and test it in your local app or API flow.

Related Tools

🔐
JWT Decoder / Inspector
Decode JWT header, payload, signature and inspect claims
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HMAC Generator
Generate HMAC signatures with SHA-256, SHA-512 and more
 📦
Base64 Encode / Decode
Encode or decode text and files to Base64
Understand JWT Builder ▾
Example
Input Header: {"alg":"HS256","typ":"JWT"}
Output Payload: {"sub":"user123","exp":1735689600,"role":"admin"}
Common Use Cases
  • Generate test JWTs for local auth and API development
  • Experiment with header and payload claims before wiring backend issuance
  • Create short-lived tokens to verify expiry and role-based logic
  • Produce HMAC-signed JWT samples for documentation or demos
Why Use This Tool
  • Useful for local auth testing without wiring a full token service.
  • Helps you experiment with claims, expiry, and HMAC algorithms quickly.
  • Runs client-side so secrets stay in the browser during token generation.
Frequently Asked Questions
Can I use RS256 (asymmetric) signing?

No. This builder is focused on HMAC signing modes such as HS256, HS384, and HS512. Use a dedicated JWT tool or backend library for RSA and EC key-based signing.

How do I decode an existing JWT?

Use the JWT Decoder tool to inspect any JWT without a secret.

What does JWT Builder / Generator - Create JSON Web Tokens do?

JWT Builder / Generator - Create JSON Web Tokens runs entirely in your browser and helps you complete this task without uploading data to a server.

Is JWT Builder / Generator - Create JSON Web Tokens free to use?

Yes. This tool is free to use and does not require sign-up.