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JWT Decoder

Decode JWT header and payload data locally, including readable time claims.

This decoder reads the token contents locally. It does not verify the signature or prove that the token is trustworthy.

Decoded token

How to use

Inspect JSON Web Token segments, pretty-print the header and payload, and convert iat, nbf, and exp values into ISO dates.

  1. Paste a token containing header, payload, and signature segments.
  2. Decode the Base64URL header and payload locally.
  3. Review JSON claims and readable iat, nbf, or exp dates.

Best for

  • Authentication debugging
  • Token expiration checks
  • OAuth and API testing

Why the result matters

  • Decoding shows what a token claims but does not verify its signature or trustworthiness.
  • Readable time claims make expiration and issue-time debugging faster.

Example inputs

  • Inspect an access token payload
  • Convert an exp claim to ISO time
  • Check the declared signing algorithm

FAQ

Does this verify the JWT signature?

No. It only decodes the token structure and never claims that the signature is valid.

Does the token leave my browser?

No. Decoding is performed locally.

Which time claims are converted?

Numeric iat, nbf, and exp claims are converted into ISO date strings.

Why can a readable token still be invalid?

JWT contents are encoded rather than encrypted, and validity depends on signature verification and application rules.