JWT Decoder
Reads JWT header and payload without verifying the signature. It is a debugging viewer, not an authentication decision tool.
Runs in your browser. Input, settings, and results are not sent to Utilio servers.
JWT Decoder
Local browser processing. Data stays on this device.
Looks valid
Signature is decoded only, not verified.
The JWT was split into header and payload. 2 claim fields were found; the signature is not verified here.
- iat
- 2024-03-09T16:00:00.000Z
- exp
- 2024-03-09T17:00:00.000Z
What JWT Decoder does
Use JWT Decoder when you need to inspect token claims, issuer, audience, and expiry while debugging.
When to use it
- Inspect token claims, issuer, audience, and expiry while debugging.
- Check whether a JWT is structurally readable.
- Copy decoded header or payload for local analysis.
How to use it
- Paste the JWT string.
- Read decoded header and payload.
- Verify the signature separately in your backend or auth tooling.
What to check
- Decoded does not mean trusted.
- Do not paste live user tokens from production systems.
Data, formats, and limits
What stays on your device and what is sent
Runs in your browser. Input, settings, and results are not sent to Utilio servers.
Supported formats
This tool works with typed or generated values rather than uploaded files.
File limits and browser requirements
- Use an up-to-date browser and check the result on the device where you will use it.
Known limits
- This tool helps inspect or transform data, but it does not replace code review, security review, or production configuration checks.
- Do not paste real secrets, tokens, or private keys into data you are not prepared to expose in the browser.
Troubleshooting
- If validation fails, start with quotes, commas, brackets, whitespace, and input encoding.
- If the result is unexpectedly empty, check the tool mode and a minimal example without extra fields.
- Do not paste real tokens, passwords, or keys; use a test snippet with the same format for diagnosis.
Common questions
What does Utilio receive?
Runs in your browser. Input, settings, and results are not sent to Utilio servers.
What is it useful for?
Use it when you need to inspect token claims, issuer, audience, and expiry while debugging. Start by pasting the JWT string.
Do I need an account?
No. You can use this tool without creating an account.
Can I use it on a phone?
Yes. The tool works in a mobile browser, though longer input or detailed results may be easier to review on a larger screen.
How do I get a reliable result?
Paste the JWT string. Then read decoded header and payload. Decoded does not mean trusted.
Does Utilio use my input or results to train AI?
No. Utilio does not use files, pasted text, settings, generated values, or results from this tool to train AI models.