JWT Decoder

Why Decode JWTs?

JSON Web Tokens (JWT) are the standard for stateless authentication in modern APIs. Debugging auth issues requires inspecting the token's header (algorithm), payload (claims, expiry), and signature. Our decoder splits the token instantly and flags whether it has expired.

Features

  • Header inspection — see the signing algorithm (HS256, RS256, etc.) and token type.
  • Payload decoding — all claims displayed as formatted JSON.
  • Expiration badge — green “Valid” or red “Expired” indicator.
  • Human-readable timestamps — iat and exp shown as local dates.
  • Signature display — the raw signature string for verification reference.

Common Use Cases

  • Debugging 401 errors by inspecting token expiration and claims.
  • Verifying that OAuth providers return the expected scopes and audience.
  • Checking token structure during API integration testing.
  • Learning JWT anatomy for security training or documentation.

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