Question 1

What is a JWT?

Accepted Answer

A JSON Web Token (JWT) is a compact, URL-safe token used to represent claims between two parties. It consists of three Base64url-encoded parts: header (algorithm and type), payload (claims like user ID, role, expiry), and signature (verifies authenticity).

Question 2

Is it safe to decode JWTs here?

Accepted Answer

Yes. Decoding runs entirely in your browser. The token is never sent to any server. However, never share JWTs containing sensitive data in public forums, even if decoded.

Question 3

Can this tool verify the JWT signature?

Accepted Answer

No. Signature verification requires the secret key, which only your server should have. This tool decodes and inspects the payload only.

Question 4

Why does my JWT say "expired"?

Accepted Answer

The exp claim in the payload contains a Unix timestamp for when the token expires. This tool compares that with the current time to show if it has expired.

JWT Decoder

Frequently Asked Questions

JWT Decoder

Frequently Asked Questions

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