api tool
JWT Decoder
Inspect JWT claims in your browser. This decoder does not verify signatures.
Paste data here. It stays in your browser.
Copy-ready result appears here.
How it works
- Splits the token into parts.
- Base64URL decodes header and payload.
- Displays formatted JSON.
Common use cases
- Debug auth claims.
- Inspect token expiration.
- Check development tokens.
Decode is not verify
This tool decodes the header and payload so you can inspect claims. It does not verify the token signature and cannot prove that a token is trustworthy.
Security caution
Avoid pasting production secrets or bearer tokens into third-party tools. This page is designed for local browser processing, but sensitive token handling should still be deliberate.
FAQ
Is my input uploaded?
No. This MVP runs tool logic in your browser and does not send tool input to a server.
Can I use this on mobile?
Yes. Pages are mobile-first and designed for quick copy, paste, and share workflows.
Does this verify JWT signatures?
No. It only decodes header and payload for inspection.
Does the tool store history?
No. The MVP does not store tool input history or create user accounts.
Should I verify important output?
Yes. These tools are designed for productivity, but production changes and financial decisions should be independently verified.
Can the tool run after the page loads?
Yes. The interactive logic runs in the browser once the static page and JavaScript island are loaded.
What input format should I use?
Use the examples on the page as a starting point, then replace them with your own local input.