Local · Private

JWT Decoder

Decode a JSON Web Token into readable header and payload — parsed on your device, with human claim dates and expiry status. The signature is never sent anywhere.

Paste a JWT

Files never leave your browser. Decoding happens entirely on your device — the secret/signature is never required or transmitted.

Decoded

Header (red)

Payload (green)

Registered claims

Standard time claims interpreted as human dates (your local timezone and UTC).

Signature

NOT verified. This tool only decodes the token — it does not check the signature, because that needs the issuer's secret or public key. Do not trust a decoded token's contents as authentic without verifying the signature on a trusted server.

About JWT Decoder

JWT Decoder is a free, private text & code tool that runs entirely in your web browser. Decode a JWT’s header & payload locally (no data sent). Because everything happens locally on your device, your files and data are never uploaded to a server, there is no sign-up or installation required, and it keeps working offline. It is handy for jwt, token, decode, json web token. Like every HeroTool by Digital Heroes, JWT Decoder is 100% free with no limits.

Frequently asked questions

Is JWT Decoder free?

Yes — JWT Decoder is completely free for everyone. No sign-up, no account and no usage limits.

Is it private? Are my files uploaded anywhere?

No. JWT Decoder runs entirely in your browser on your own device, so your data never leaves your computer and nothing is uploaded to a server.

Does it work offline?

Yes. HeroTools is a Progressive Web App — once the page has loaded it keeps working offline, and you can install it as an app from your browser.

Do I need to install anything or create an account?

No. Just open the page and start using it. Installing it as an app is optional and only adds offline convenience.

What does JWT Decoder do?

Decode a JWT’s header & payload locally (no data sent).