JWT Encoder/Decoder

No. Decoding just base64url-decodes the header and payload so you can read the claims — it does not prove the token is authentic. To actually verify a signature you need the correct secret or public key entered here.

Decoding and signing happen entirely in your browser — the token and any secret you enter are never sent to a server. Still, treat tokens from production systems carefully, since anyone who sees a decoded JWT can read its claims.

The Expired/Valid indicator here only compares the exp claim to the current time — it doesn't check clock skew tolerances or other validation rules your server or library might apply.