Decode any JWT token into its header, payload, and signature — instantly, privately, and without sending your token to any server.
JWT (JSON Web Token) is the standard format for authentication tokens in modern web applications. When debugging auth flows, inspecting claims, or verifying token structure, you need to decode the Base64url-encoded token into readable JSON. Our JWT Decoder breaks down any JWT into its three components — header, payload, and signature — without sending your token to any server.
This is critical for security: never paste JWTs into online tools that send data to servers. Our decoder runs 100% in your browser.
A JWT consists of three Base64url-encoded sections separated by dots: the Header (algorithm and token type), the Payload (claims — user data, expiry, issuer), and the Signature (cryptographic verification). Only the signature requires the secret key to verify.
No. Signature verification requires the secret key or public key, which should never be entered into any online tool. This decoder only decodes the header and payload — it does not verify authenticity. Always verify signatures server-side.
Yes — our decoder runs entirely in your browser. Your JWT is never sent to UtilDash servers. That said, as a general security practice, avoid pasting production JWTs containing sensitive user data into any browser tool when not necessary.
iat (issued at) is the Unix timestamp when the token was created. exp (expiration) is when the token becomes invalid. nbf (not before) is the earliest time the token is valid. All three are Unix timestamps.
All processing happens locally in your browser. We never see, store, or transmit your data. This tool is fully client-side and secure.
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