JWT Decoder input is rejected
The source data may be incomplete, malformed, or different from the format this tool expects.
Check the input hint, try a small sample first, and correct the source file before running the full job.
Use this tool
Prepare the input and run the tool
Paste the text or structured data for this tool, Set options. Result: Copy result, Review issue report.
Ready. Paste a JWT and click Decode.
Decoded header and payload output appears here.
Data handling: Files and pasted data are processed in this browser session.
Tool guide
How to use JWT Decoder
Use JWT Decoder when you need to check, convert, or prepare a file before using it in another app. Review the result before downloading or copying it.
What this tool does
Decode JWT tokens locally in your browser and inspect header and payload without validating the signature.
- Input
- Paste the text or structured data for this tool, Set options
- Output
- Copy result, Review issue report
Tool advantages
- Runs in this page; the file or pasted data is not sent to a new app.
- Keeps the preview, report, and download in the same screen.
- Gives you a report you can use as a cleanup list.
Step-by-step usage guide
- 1Add your data and confirm the options.
- 2Run JWT Decoder.
- 3Review the report and copy or download the result.
Common errors and fixes
JWT Decoder result looks incomplete
The preview can only use the rows, files, or fields provided in the current browser session.
Confirm that the full source was pasted or selected, then rerun the tool and review the output before downloading.
JWT Decoder output needs extra cleanup
Some destination systems have rules that are stricter than a browser-local utility can infer.
Use the report as a cleanup checklist and verify the final file in the app where it will be imported or shared.
When to use JWT Decoder
- You are checking files before an upload, import, share, or delivery.
- You want to confirm the result before sending it to another system.
- You need a copied result, downloaded file, or report that can be reviewed outside the page.
FAQ
Is my token uploaded anywhere?
No. The token is processed only in your browser and never sent to a server.
Does this verify the JWT signature?
No. This tool is decoded-only and does not verify the signature.
What happens with an invalid token?
You will get a clear parse error and the tool will not throw a runtime exception.