JWT Decoder Online
Paste a JSON Web Token to decode the header and payload, inspect claims, and view expiration times. This tool only decodes; it does not verify signatures.
How To Use
- Paste or generate the content in the tool area.
- Run the primary action such as validate, encode, decode, or generate.
- Review the result, error message, or expiration viewer.
- Copy or download the output for development use.
Best Practices
- Keep sensitive production secrets out of online tools.
- Validate generated output before using it in production.
- Prefer local, browser-only utilities for quick debugging.
- Save repeatable examples as fixtures for future tests.
Common Mistakes
- Confusing encoding with encryption or signature verification.
- Copying stale output after changing input.
- Ignoring parser errors that point to a specific syntax location.
- Using identifiers or decoded tokens as security secrets.
FAQ
Does this JWT decoder verify signatures?
No. It only decodes the header and payload so you can inspect claims. It does not validate the token signature.
Is it safe to paste a JWT here?
Decoding runs locally in your browser, but you should still avoid pasting production secrets or sensitive user tokens into any tool.
What parts does a JWT contain?
A JWT usually has three dot-separated parts: header, payload, and signature.
How is the expiration time shown?
If the payload has an exp claim, the tool converts the Unix timestamp into a readable local date and UTC date.
What is the iat claim?
iat means issued at. It is a Unix timestamp showing when the token was created.
Why can a JWT be decoded without a secret?
JWT header and payload are Base64URL encoded, not encrypted. The secret is needed for signature verification, not decoding.
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