JWT Decoder
Read JWT header and payload claims.
How to use the JWT Decoder
Paste your input
Drop the snippet, token or document into the editor. Invalid characters are highlighted as soon as parsing fails.
Choose how to process it
Select formatting, validation or conversion options. Results are calculated as you type, with no submission step.
Copy or download
Use the copy button for a clean result, or download it when the output is large.
What JWT Decoder is for
Paste a JSON Web Token to decode its header and payload, inspect expiry timestamps and see which signing algorithm was used. Verification is not attempted unless you provide the secret.
The JWT Decoder is part of the Developer collection on ToolFlow. It is designed for one concrete job: read JWT header and payload claims. Everything runs client-side, so you can use it with sensitive material without creating a copy on someone else's server.
Common use cases
- Debug an auth flow
- Check token expiry
- Inspect custom claims
Good to know
- No account is required, and there is no usage limit on the browser tool.
- Processing happens locally. Files are read from disk and the result is written back to your downloads folder.
- Results are reproducible: the same input and options produce the same output, with no hidden server round-trip.
- If the tool needs a live data source, the page states it explicitly instead of silently failing.
JWT Decoder FAQ
The questions people ask before using this tool.