JWT Decoder

About this calculator

This tool decodes a JSON Web Token (JWT) by base64url-decoding its three dot-separated parts — the header (algorithm and token type), payload (claims like user ID, issuer, and expiry), and signature — and displays the header and payload as readable JSON. It does not verify the signature, so it can't confirm the token is authentic or unmodified.

Backend developers debugging authentication flows, and anyone integrating with an API that uses JWT-based auth, use it to quickly inspect what claims a token carries — such as its expiry (exp) or subject (sub) — without writing decoding code. Paste a JWT to see its decoded header and payload.