JWT オンラインジェネレーター
カスタムペイロードと秘密鍵から HS256 署名の JWT トークンを生成します。
アルゴリズム：HS256（HMAC-SHA256）。署名はブラウザ内で完結します。
What Is JWT Generator?
JWT Generator is a free online tool that creates signed JSON Web Tokens (JWTs) using the HS256 algorithm. Paste your JSON payload, enter a secret key, and the tool produces a valid JWT token — making it ideal for testing APIs, debugging authentication flows, and learning how JWTs work.
How to Use JWT Generator
- Edit the JSON payload in the left panel with your desired claims (sub, name, exp, etc.).
- Enter your HMAC secret key in the secret field.
- Click Generate to create the signed JWT token.
- Copy the token to use in your API requests or tests.
Features
- Generates HS256-signed JWT tokens
- Color-coded token parts: header (red), payload (blue), signature (green)
- Signing performed in-browser via Web Crypto API
- Copy token to clipboard
- Runs entirely in your browser — zero data uploaded
FAQ
What signing algorithm does JWT Generator use?
JWT Generator uses HMAC-SHA256 (HS256), the most widely used symmetric signing algorithm for JWTs. The secret key is used for both signing and verification.
What should I put in the payload?
The payload is a JSON object containing claims. Common claims include sub (subject), name, iat (issued at), and exp (expiration time as a Unix timestamp).
Is my secret key sent to a server?
No. JWT signing is performed entirely in your browser using the Web Crypto API. Your secret key and payload never leave your device.