100% Client-Side

JWT Builder

Free online JWT builder. Create and sign JSON Web Tokens with custom payloads using HS256 via Web Crypto. 100% client-side. — runs 100% in your browser, client-side only. No data is sent to any server. Free to use, no account required.

Free Client-Side No Login No Storage
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JWT Decoder & Inspector Decode and inspect JWT tokens — header, payload, claims at a glance JWT Encoder Create and sign JWT tokens with custom claims and headers HMAC Generator Generate HMAC message authentication codes — SHA256, SHA512, SHA1, MD5

How to Use the JWT Builder

  1. Edit the JSON payload with your claims (sub, iat, exp, etc.).
  2. Choose HS256 or none (unsigned).
  3. Enter a secret key for HS256.
  4. Click Sign JWT.

Uses Web Crypto HMAC-SHA256 for signing. No data leaves your browser.