JWT Decoder
Decode and inspect JSON Web Tokens
JWT Decoder is a free online tool from BrowserUtils that decode and inspect json web tokens. It runs entirely in your browser — your data never leaves your device. No account required.
How to use JWT Decoder
- 1 Paste or type your input into the editor above.
- 2 The tool processes your data instantly — right in your browser, with nothing sent to a server.
- 3 Copy the result with one click or continue editing your input.
About JWT Decoder
Free online JWT decoder. Paste a JSON Web Token to decode and inspect its header, payload, and signature. This tool runs entirely in your browser — your data is never sent to a server. Just paste your input, get instant results, and copy with one click. No sign-up or installation required.
JWT Decoder specs
- Runtime
- 100% client-side (browser)
- Built on
- TextEncoder, TextDecoder, btoa/atob, and encodeURIComponent — all Web Platform APIs
- Cost
- Free — no account, no rate limits, no usage caps
- Browser support
- Chrome 90+, Firefox 88+, Safari 14+, Edge 90+
- Part of
- 299 developer tools on BrowserUtils (100% client-side)
Questions
Is it safe to decode JWTs online?
This tool runs entirely in your browser. Your token never leaves your device and is not sent to any server.
Can this tool verify JWT signatures?
This tool decodes and displays the JWT contents. Signature verification requires the secret key or public key, which is not handled by this decoder.
What are the three parts of a JWT?
A JWT has three Base64url-encoded parts separated by dots: the header (algorithm and token type), the payload (claims like user ID and expiration), and the signature (used to verify the token was not tampered with).
How do I check if a JWT has expired?
Decode the JWT and look at the "exp" claim in the payload. This is a Unix timestamp representing the expiration time. Compare it to the current time to determine if the token is still valid.
What is the difference between a JWT and a session cookie?
A session cookie stores a reference ID on the server, while a JWT contains the actual user data and is verified by its signature. JWTs are stateless and do not require server-side session storage.
Can I decode a JWT from an Authorization header?
Yes, copy the token value after "Bearer " in the Authorization header and paste it into the decoder. The tool will display the header, payload, and signature sections.
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