JWT header and payload decoder
Inspect token claims during API development and debugging.
How it works
Base64URL header and payload segments are decoded and displayed as JSON.
Technical limitation
Decoded claims are untrusted. This tool does not verify the signature, issuer, audience, expiry, or authorization.
Privacy
Input stays in this browser and is not intentionally uploaded.
A practical guide to JWT header and payload decoder
Decode JWT header and payload data locally without verifying its signature. This page handles one focused task so you can reach a result without creating an account. The core operation runs in the current browser unless an external resource is clearly identified.
How to get a reliable result
- Begin with a clean source value or file and confirm that every selected unit and option matches your goal.
- Run the tool, then compare the result with the original requirement instead of relying only on a success message.
- Copy or download the output and test it in the destination where it will actually be used.
Limitations and good practice
Decoded data does not prove that a token is genuine. This viewer does not verify signatures or authorization. Keep an untouched copy of important source material. Browser support, rounding, source quality, encoding, and platform rules can affect results.
Frequently asked questions
Is this tool free?
Yes. No account or credits are required. Normal internet data charges may still apply.
Does the site retain my input?
The core task runs in the browser and the site does not intentionally retain the submitted value or selected file. External libraries and links have their own policies.
Should I verify the output?
Yes. Review calculations, code, files, and images before using them for financial, legal, accessibility, security, or production decisions.