🔑 JWT Decoder
Paste a JSON Web Token to instantly decode and inspect its header and payload. Nothing leaves your browser.
What is a JWT?
A JSON Web Token (JWT) is a compact, URL-safe token format used for authentication and information exchange. It consists of three Base64URL-encoded parts separated by dots:
Header — specifies the token type and signing algorithm (e.g. HS256, RS256).
Payload — contains the claims: data like user ID, roles, expiry (exp), issued-at (iat), etc.
Signature — used to verify the token hasn't been tampered with. Verification requires the secret key and is not performed here.
This tool only decodes the token — it does not verify the signature. Never trust a JWT's claims without verifying the signature on your server.