▶ Interactive Lab

JWT Decoder

Paste a JWT; see header, payload, and claim breakdown.

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JWTs have three base64url-encoded parts: header.payload.signature.

What you're seeing

JSON Web Tokens carry claims in three dot-separated base64url-encoded parts: header (algorithm), payload (claims), signature (verifying integrity).

Anyone can decode the payload — JWTs are signed, not encrypted. Never put secrets in claims. Standard claims: iss (issuer), sub (subject), aud (audience), exp (expiry), iat (issued at), nbf (not before).

★ KEY TAKEAWAY
JWTs are signed, not encrypted. Anyone can decode the payload — never put secrets in claims.
▶ WHAT TO TRY
  • Paste a JWT or use the sample.
  • See the three base64url parts: header, payload, signature.
  • Check the expiry — exp claim tells you if it's still valid.