JWT Decoder 🔒 Your data never leaves your browser.
Decode JWT header & payload, check expiration. Nothing is sent anywhere.
About this tool
A JWT (JSON Web Token) has 3 dot-separated parts: header, payload and signature. The header and payload are just Base64URL-encoded JSON — anyone holding the token can read them, which is why you should never put sensitive data in a JWT payload. This tool decodes the token, checks expiration (exp/nbf) and explains each standard claim.
Unlike many JWT decoders, everything here runs 100% in your browser — your token (which often carries live session credentials) is never sent to any server.