JWT Decoder
Header / Payload / Signature with expiry check
🔒 All data is processed in your browser. Nothing is uploaded to any server.
Header
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Payload
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Signature
—
Decodes only — does not verify signature.
Quick guide
What can JWT Decoder help you do?
Free JWT decoder. Shows header, payload, signature, and expiry status. Browser-only — your token stays private.
Best for
Useful for quick file work, text cleanup, calculations, content creation, and website or AI checks.
How to use it
Open the tool, enter or upload what it asks for, then copy or download the result directly.
Privacy and limits
Most tools run in your browser with no sign-in. Very large files or older devices may hit browser memory limits.
Frequently Asked Questions
What is a JWT?
JSON Web Token — three Base64-encoded parts used for API auth and sessions.
Does this verify signatures?
No — verification requires the secret key from your server.