JWT Decoder

This value is never sent to a server. Everything runs locally in your browser.

Paste a JWT token (xxx.yyy.zzz) to instantly view its Header/Payload as pretty-printed JSON.

This tool does not support signature verification. It only decodes the Header/Payload, so it cannot confirm whether the token is authentic (unmodified).

JWT token

What is this?

A JWT (JSON Web Token) is three dot-separated parts — header.payload.signature — commonly used to carry authentication state between services statelessly (without server-side sessions). The header describes the signing algorithm, the payload holds claims like the user ID or expiration time (exp), and the signature proves the token hasn't been tampered with. As noted above, this tool only decodes the header/payload for readability and does not verify the signature, so confirming a token's authenticity requires separate verification logic.