Question 1

What is a JWT?

Accepted Answer

JWT (JSON Web Token) is a compact, URL-safe token format consisting of three Base64URL-encoded sections: header, payload, and signature. It is widely used for stateless authentication — the server embeds user claims in the token and verifies the signature on each request.

Question 2

Is it safe to decode a JWT in the browser?

Accepted Answer

Decoding (reading) a JWT is always safe — the header and payload are just Base64URL-encoded JSON, not encrypted. However, never share your JWT with untrusted parties, as it grants access to your session. This tool decodes client-side only; your token is never sent to any server.

Question 3

Can I verify a JWT signature with this tool?

Accepted Answer

This tool decodes the header and payload for inspection. Full signature verification requires the secret key (HS256) or public key (RS256) used to sign the token. For security-critical verification, always validate server-side using a trusted JWT library.

JWT 디코더 라이트

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