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Paste a JSON Web Token and instantly see its decoded header, payload, and signature. The decoder parses the three Base64URL-encoded segments and presents them as formatted JSON, making it easy to inspect claims, expiration times, and signing algorithms without writing any code.
A JWT consists of three parts separated by dots: the header (which specifies the algorithm and token type), the payload (which carries the claims — data like user ID, roles, and expiration), and the signature (which verifies the token has not been tampered with). This tool decodes the first two parts, which are simply Base64URL-encoded JSON. It does not verify the signature, since that requires the signing key.
Inspect the claims inside an access token to troubleshoot authentication or authorization issues.
Quickly see when a token was issued and when it expires without decoding manually.
Review what data is stored in a JWT to ensure no sensitive information is exposed in the payload.
Visualize the JWT structure to understand how claims-based authentication works.
No. Signature verification requires the secret key or public key, which this client-side tool does not have. It only decodes the header and payload.
Yes. Everything runs in your browser. The token is never sent to any server.
"exp" is the expiration time and "iat" is the issued-at time. Both are Unix timestamps representing seconds since January 1, 1970.
All processing happens directly in your browser. Your files never leave your device and are never uploaded to any server.