JWT Decoder

Decode and inspect JSON Web Tokens securely.

About JWT Decoder

The JWT Decoder allows you to safely unpack and inspect the header and payload claims of JSON Web Tokens without needing the secret key.

How to use

Paste your JWT string into the input field. The tool instantly decodes the Base64Url-encoded segments and displays the JSON payload, highlighting expiration times and issuer details.

Why use this tool?

JSON Web Tokens often contain sensitive session or user data. Decoding them locally is crucial to prevent token leakage to unauthorized third-party logging servers.

Frequently Asked Questions

Do I need the secret key to decode a JWT?

No. The header and payload of a JWT are Base64Url-encoded — not encrypted — so they can be decoded without the secret key. The signature can only be verified with the key.

Is it safe to paste my JWTs here?

Yes. Decoding happens entirely in your browser with no network requests. Your tokens are never sent to any server.

Can I see when a token expires?

Absolutely. The tool automatically detects the 'exp' (expiration), 'iat' (issued at), and 'nbf' (not before) timestamp claims and displays them as human-readable dates.

Is JWT Decoder free to use?

Yes, JWT Decoder is completely free to use with no account, subscription, or hidden fees required — ever.

Does my data get uploaded to a server?

No. JWT Decoder processes everything directly inside your browser using modern Web APIs. Your data is never sent to any server, ensuring complete privacy.