JWT Decoder
Decode and inspect JSON Web Tokens without verification. Nothing leaves your browser.
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How to Use JWT Decoder
Decode JSON Web Tokens (JWT) to inspect header, payload, and signature. See expiration status. 100% client-side, no verification.
Type directly into the input field, paste from your clipboard, or upload a file. The tool accepts a wide range of inputs and handles edge cases automatically.
Click the action button or watch as the tool processes your input in real time. All computation happens locally in your browser - nothing is sent to any server.
Copy the output to your clipboard with one click, or download it as a file. Your data stays private throughout the entire process.
Why Choose PrivConvert?
Unlike other online tools that upload your files to remote servers, store them for days, and may use them for AI training or data mining, PrivConvert was built with privacy as the foundation.
Files are processed in volatile memory (RAM) and immediately purged. Nothing is ever written to disk or backed up.
All uploads and downloads are encrypted with TLS 1.3. Your files cannot be intercepted in transit.
Use any tool instantly without signing up, providing an email, or creating a profile. No tracking cookies, no user profiling.
Compatible with Windows, macOS, Linux, iOS, and Android. No plugins or desktop software needed - just a modern web browser.
Trusted by Thousands of Users
PrivConvert processes thousands of file conversions every day. Our commitment to privacy and security has made us the go-to choice for professionals, developers, and privacy-conscious users worldwide.
Frequently Asked Questions
Is JWT Decoder free to use?
Yes, completely free with no limits, no sign-up, and no hidden fees. Use it as many times as you want.
Is my data safe?
All processing happens directly in your browser. Your data is never sent to any server, never stored, and never shared. It's 100% client-side.
Does it work on mobile devices?
Yes. The tool works on any device with a modern web browser - smartphones, tablets, laptops, and desktops.
Do I need to create an account?
No. You can use the tool instantly without signing up, providing an email, or creating any profile.
This decodes, it does not verify — and that distinction matters
A JWT is three base64url-encoded parts separated by dots: a header, a payload and a signature. The first two are encoded, not encrypted. Anyone holding the token can read them, which is why this tool can show you the contents without a key and why you must never put a secret in a JWT payload.
What this tool does not do is check the signature, and that is a deliberate limitation rather than a missing feature. Verifying requires the signing key: the shared secret for HMAC algorithms, or the public key for RSA and ECDSA. Pasting a production signing secret into a web page is precisely the thing you should never do, so no responsible online decoder asks for one.
What decoding is genuinely useful for
- Expiry. The
expclaim is a Unix timestamp, and "the token expired forty minutes ago" explains a great many mysterious 401s. - Clock skew. An
nbf(not before) in the future means the issuing server's clock is ahead of the validating server's. - Audience and issuer. A token minted for the staging
audwill be rejected by production, and the payload says so. - Claim shape. Confirming the roles or scopes your authorisation logic reads are actually present and named as expected.
The alg: none trap
The header names the signing algorithm, and some older libraries would trust
it — so a token whose header said "alg": "none" would be accepted
unsigned. If your service verifies JWTs, it must require the algorithm it expects
rather than reading it from the token. Decoding a token is a quick way to see
what a client is actually sending.
Everything happens in your browser. The token is not transmitted, which matters because a JWT you are debugging is usually a live credential.