ToolBox

JWT Decoder

Decode a JWT's header and payload. Decoding is not signature verification.

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Header

{
"alg": "HS256",
"typ": "JWT"
}

Payload

{
"sub": "1234567890",
"name": "John Doe",
"iat": 1516239022
}

The signature is not verified here — decoding only reveals the header and payload. Never trust a JWT's contents without verifying its signature on a server that holds the secret or public key.

Your file never leaves this browser tab — everything runs locally on your device.

How to use jwt decoder

  1. Paste a JWT (the three dot-separated parts).
  2. Click "Decode JWT".
  3. Review the decoded header and payload as formatted JSON.

Common use cases

  • Inspecting the claims inside an access or ID token while debugging auth.
  • Checking a token's expiry (exp) or issued-at (iat) time.
  • Understanding what a third-party API's JWT actually contains.

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Frequently asked questions