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JWT inspector
Decode the readable contents of a JSON Web Token locally and inspect its claims without sending the token to a server.
- 100% local
- Instant
- Free
- No account
- Works offline
- Clipboard
Data not sent
Result
Why use this tool?
Inspect a JWT header, payload, and important timestamps locally to understand its contents without sending the token to a server. It is useful for authentication debugging, checking claims, or reading expiry data, but it does not replace cryptographic signature verification.
Smart processing
Generate or verify sensitive data with clear and immediate controls.
Supported formats
Strings, keys, hashes, and technical formats depending on the security function.
Save time
Get a clean, ready-to-use result in seconds without installing software or configuring a complex workflow.
Guide
How to use this tool
- 1
Paste the complete JWT
Add the token without changing its three dot-separated sections.
- 2
Inspect header and payload
Review the declared algorithm, claims, and timestamps such as iat, nbf, or exp when present.
- 3
Interpret the data carefully
Use decoded information for diagnosis, but have the server verify the signature before trusting the token.
Tips and best practices
- Decoding a JWT does not prove authenticity; the signature must be verified using the expected key and algorithm.
- Avoid sharing real JWTs that contain sensitive information, even when they are expired.
- Check timestamps such as exp, nbf, and iat against the clock and timezone assumptions of the relevant system.
Frequently asked questions
What is the difference between decoding and verifying a JWT?
Decoding makes the header and payload readable. Cryptographic verification confirms that the signature matches an expected key and algorithm.
Is a decoded JWT automatically valid?
No. Any correctly structured token can be decoded; the signature and claims still need to be validated before trusting it.
Can the tool check expiration?
It can display time-based claims such as exp when present, but that is separate from full server-side token validation.
Is the JWT uploaded to the Internet?
No. Inspection runs locally in your browser.
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