JWT Decoder Online
Decode and inspect JSON Web Tokens — header, payload, and signature — in your browser.
What Is JWT Decoding?
JWT Decoder is a free online tool that decode and inspect JSON Web Tokens — header, payload, and signature — in your browser. No files are uploaded — everything is processed locally on your device.
This JWT decoder online free parses the three Base64-encoded sections of a JSON Web Token — the header, payload, and signature — into readable JSON. JWTs are widely used in authentication and authorization flows across modern web applications. Our decoder lets you inspect token claims, expiration times, and signing algorithms directly in your browser without sending sensitive tokens to any external service.
Privacy guarantee: JWT Decoder processes all files directly in your browser using WebAssembly. No data is uploaded to any server, no information is collected, and the tool works offline after loading. Unlimited usage with no signup, no watermarks, and no file size limits.
How to Use JWT Decoder
Paste your JWT
Copy your JSON Web Token and paste it into the input field.
Inspect decoded sections
Instantly see the header, payload, and signature decoded into readable JSON.
Inspect claims and expiry
Review token claims such as issuer, subject, expiration time, and custom data.
Why Use Our JWT Decoder?
Frequently Asked Questions
Does this tool verify the JWT signature?
It decodes but does not verify by default. The tool displays all three sections of the JWT, and signature verification requires the secret key or public key, which you can optionally provide to validate the token.
Is it safe to paste my JWT into an online tool?
With our decoder, yes. The entire decoding process happens in your browser. The token is never transmitted to any server or stored anywhere. For production tokens, always prefer client-side tools like this one.
What information can I see in a decoded JWT?
The header, payload claims, and signature data. The header reveals the signing algorithm and token type. The payload contains claims such as the issuer (iss), subject (sub), expiration time (exp), issued-at time (iat), and any custom claims added by the application.
Why should I use a private JWT decoder instead of jwt.io?
For privacy — this decoder never sends your token to any server. jwt.io sends your token to their server for verification by default. If your JWT contains production user data, session identifiers, or API credentials, a client-side decoder like this one ensures that sensitive token data never leaves your browser.
How do I check if a JWT token has expired?
Paste the JWT into the decoder and look at the "exp" (expiration) claim in the payload. The decoder displays this as both a Unix timestamp and a human-readable date, making it easy to see if the token is still valid.
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