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JWT Decoder

FreePrivateDecode only

Paste a JWT to inspect the header and payload. Decoding runs locally; signatures are not verified.

JWT
Header
Payload
Claims
N/A
Ctrl+Enter Decode

Decode JWT Token Online

Paste any JSON Web Token to instantly read its header, payload claims, and expiry time. JWTs are made up of three Base64url-encoded segments separated by dots. This tool decodes each segment so you can inspect iss, sub, aud, exp, and any custom claims without leaving your browser or uploading sensitive data to a third party.

How to Use

  1. Paste the full JWT string (three dot-separated segments) into the input field
  2. Click Decode to parse the header and payload
  3. Read the decoded JSON claims; check the expiry field if an exp claim is present

JWT Structure

Encoded JWT (three segments)
eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9
.eyJzdWIiOiIxMjM0IiwibmFtZSI6IkFsaWNlIiwiZXhwIjoxOTAwMDAwMDAwfQ
.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c
Decoded payload
{
  "sub": "1234",
  "name": "Alice",
  "exp": 1900000000
}

Features

  • Decodes header and payload from any standard JWT format
  • Displays exp as a human-readable UTC timestamp and indicates if the token has expired
  • Shows the algorithm (alg) and token type (typ) from the header
  • Highlights registered claims: iss, sub, aud, iat, and nbf
  • Runs entirely in your browser. no token data is sent to any server
  • Works with JWTs from OAuth 2.0, OpenID Connect, and custom auth systems

Frequently Asked Questions

What is a JWT token?

A JSON Web Token (JWT) is a compact, URL-safe string used to represent claims between two parties. It consists of three Base64url-encoded segments separated by dots: a header describing the algorithm, a payload containing the claims, and a signature used to verify integrity.

Is it safe to decode a JWT here?

Yes. Decoding runs entirely in your browser using JavaScript. Your token is never sent to any server. This makes the tool safe for tokens that contain sensitive claims like user IDs or email addresses.

What does the signature part of a JWT do?

The signature allows a server to verify that the header and payload have not been tampered with. It is created by the issuing server using a secret or private key. This tool does not verify the signature; it only decodes the header and payload so you can read the claims.

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