JWT Decoder
Decode a JSON Web Token’s header and payload locally.
Decoding is not verification: anyone can read a JWT, only its signature proves it wasn’t tampered with. Signature verification requires the secret or public key and is deliberately not attempted here — never paste production tokens from a live site into any web tool.
使い方
- すべてブラウザ内でローカルに動作します。データは送信されず、アカウントも不要です。
概要
Paste a JWT to see its decoded header and payload, with exp/iat timestamps shown as readable dates and a live “valid for X” status.
Decoding only reveals claims — it does not verify the signature. Never rely on a decoded token without signature verification on your server, and never paste a production token from a live system into a web tool.
すべてブラウザ内でローカルに動作します。データは送信されず、アカウントも不要です。
Embed this tool
Customize and copy an iframe. Linking back helps both sites.