The payload includes sub: learner-1 and name: Amina. The result explicitly says the signature is present but not verified.
BROWSER UTILITIES · FREE JAVASCRIPT TOOL
JWT Decoder for Header & Payload
Decode the readable header and payload of a JSON Web Token locally without claiming to verify its signature.
Free to useNo sign-upRuns in your browser
JS
JWT DecoderLocal browser processing
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Your processed result will appear here.
A WORKED TASK
Read a token payload without trusting it
The sample JWT has three dot-separated parts. Decode it to see the header algorithm label and the payload’s learner identity fields. The third part is just a sample signature string. Decoding the first two parts does not establish who issued the token or whether its data was modified.
This is a local decoder, not an authentication verifier. A token can be readable, well-formed and completely untrustworthy. Never use the decoded name as proof of identity.
What to check
- Do not paste a production session token: bearer tokens can grant account access.
- An exp field, if present, is a claim inside the token; it does not replace signature and issuer validation.
- Verify signatures, allowed algorithms, issuer, audience and expiry in the application that accepts the token.
TESTED & REVIEWED
Know what this tool does—and where to double-check
- Reviewed by
- HTML Online Viewer project
- Last reviewed
- Processing
- Ordinary processing happens in this browser tab; the tool does not intentionally upload your source.
- Important limitation
- JavaScript checks and transformations cannot prove that application logic is correct. Test the result in its real project before publishing.
PRACTICAL EXAMPLE
Start with a small JWT Decoder example
The built-in sample makes the accepted input visible before you use your own project data.Example input
Loaded in the workspace
eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiJsZWFybmVyLTEiLCJuYW1lIjoiQW1pbmEifQ.signatureRun the sample first, then change one value at a time so each result remains easy to explain.
What this example demonstrates
Decode the readable header and payload of a JSON Web Token locally without claiming to verify its signature.
Keep the original file, review the generated result and test production code in its real application before publishing.
COMMON QUESTIONS
JWT Decoder FAQ
Is JWT Decoder free?
Yes. It is free to use and requires no account.
Does JWT Decoder upload my source?
No. Ordinary processing happens locally in the current browser. The JavaScript runner uses a short-lived isolated browser worker.
Can I import and export a file with JWT Decoder?
Yes. Import a relevant JavaScript, JSON or text file, then save the input or processed result.