Decoding a JWT token is instant. Paste your JWT token (the long string with two dots separating three parts) into the input field. The decoder immediately splits it into header, payload, and signature sections. The header shows the algorithm and token type. The payload displays all claims including standard ones like 'iat' (issued at), 'exp' (expiration), and 'sub' (subject) in a readable format. Expiration status is highlighted — green for valid, red for expired. Copy any decoded section or the full JSON with one click. The tool handles both JWS and JWT tokens.
JWT (JSON Web Token) is a compact, URL-safe token format used for authentication and information exchange between parties.
Yes, decoding happens entirely in your browser. The token is never sent to any server. Note that decoding is not the same as verification.
It decodes and displays the header (algorithm, type), payload (claims like user ID, roles, expiration), and indicates the signature status.
The tool decodes and displays token contents but signature verification requires the secret key. You can paste a secret to verify HS256 tokens.
Common issues include missing parts (JWT has 3 segments separated by dots), invalid Base64 encoding, or corrupted token data.