JWT Decoder
Decode and inspect JSON Web Tokens. View header, payload, and signature instantly in your browser. No data leaves your device.
Security notice
This tool decodes tokens only — it does not verify signatures. Nothing is sent to any server. Do not paste sensitive production tokens.
How to use
- 1
Paste your JWT
Paste a JSON Web Token into the input field. The tool decodes header and payload instantly as you type.
- 2
Inspect claims
View formatted JSON for the header and payload. Time claims like exp, iat, and nbf show human-readable dates.
- 3
Copy sections
Use Copy header or Copy payload to grab decoded JSON. The signature is shown as raw text only.
Frequently Asked Questions
No. This tool only decodes Base64URL-encoded header and payload. It does not validate the cryptographic signature.
Never. Decoding happens entirely in your browser. Your token never leaves your device.
JWTs use Base64URL encoding (not standard Base64). Dashes and underscores replace plus and slash, and padding may be omitted.
If the exp (expiration) claim is in the past, the tool labels it expired. That does not mean the token was verified — only that the timestamp has passed.
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