JWT Decoder

Paste a JWT to read what is actually inside it: algorithm, claims and a human-readable expiry. It decodes only and never verifies the signature, so treat the contents as unauthenticated.

This tool decodes only. It does not verify the signature, so treat the contents as unauthenticated until your backend checks them.

How it works

A JWT is three Base64URL-encoded parts joined by dots: a header, a payload of claims, and a signature. Plybyte splits the token and decodes the first two parts so you can read exactly what it carries, and it renders any exp, iat or nbf timestamps as human dates. The signature is intentionally left untouched, because verifying it needs the secret or public key, which belongs on your server, not in a browser tool.