JWT Decoder

Decode a JSON Web Token and read its header, payload and expiry. Free, no sign-up, the token never leaves your browser.

🔒 100% private — processing happens in your browser. Nothing is uploaded.

How to use the JWT decoder

  1. Paste a JSON Web Token (with or without “Bearer ”).
  2. The header and payload are decoded instantly and shown as formatted JSON.
  3. Check the issue and expiry times — expired tokens are highlighted.

JWTs are used for login sessions and API access. The first two parts are only Base64URL-encoded, so anyone can read them — never put secrets inside. This decoder runs completely in your browser, which makes it safe to inspect real tokens: nothing is sent to a server. It does not verify the signature, because that needs your secret or public key.

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