JWT Encoder
Build and sign a JSON Web Token with HMAC — in your browser.
Algorithm
Signed in your browser with HMAC — the secret never leaves this page. Don't paste a production secret you don't control.
About JWT Encoder
A JWT encoder builds a signed JSON Web Token from your payload and secret. Enter claims and a secret, pick HS256, HS384, or HS512, and it signs the token with HMAC via the browser's Web Crypto API. Signing runs locally, so your secret is never transmitted.
Frequently asked questions
- Which algorithm should I choose?
- HS256 is the common default and interoperates everywhere. HS384 and HS512 use larger HMAC digests if your system requires them.
- Is my signing secret safe?
- Yes. The token is signed in your browser with Web Crypto; your secret and payload are never sent to a server.
- Can I decode the token I create?
- Yes — paste it into the JWT Decoder to inspect its header and payload.
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