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Client-Side JWT Token Debugger

Decode, inspect, and parse JSON Web Tokens (JWT) 100% locally in your browser. View claims, expiration dates, and verify structure with zero server transmission.

Client-Side JWT Token Debugger

Safely inspect and decode JWT tokens in the browser without sending sensitive tokens, authentication cookies, or user credentials to external servers.

Sample Presets:
🟢

Token is Active & Valid

Algorithm: HS256 • Type: JWT

Exp: 12:00:00 AM

🔴Token Header (Algorithm & Type)

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

🟣Token Payload (Claims & Data)

{
  "sub": "1234567890",
  "name": "Jane Doe",
  "admin": true,
  "iat": 1670000000,
  "exp": 2524608000
}

Parsed Standard Claims Breakdown

Claim (Key)MeaningRaw ValueHuman Interpretation
subSubject (sub)1234567890User / Entity Identifier
iatIssued At (iat)1670000000Fri, 02 Dec 2022 16:53:20 GMT (2023937 mins ago)
expExpires At (exp)2524608000Sat, 01 Jan 2050 00:00:00 GMT (12219530 mins from now)
🔒Signature Validated Offline (Structural Syntax Check Passed) • Signature length: 43 chars
Zero Server Transmission
📖

How to Decode & Debug JWT Tokens Offline

  1. 1

    Paste an encoded JSON Web Token (JWT) string into the main input box.

  2. 2

    Observe the decoded Header section to inspect the encryption algorithm (e.g. HS256, RS256) and token type.

  3. 3

    Inspect the Payload section for standard JWT claims (sub, iss, aud, iat, exp) as well as custom user claims.

  4. 4

    Review the human-readable timestamp translations and active expiration status badges.

❓

JSON Web Token (JWT) FAQ

Is it safe to paste production JWT tokens here?

Yes. Unlike other online tools, this debugger decodes base64url strings entirely in your browser. Tokens are never sent over the network or saved to any database.

What do 'iat', 'exp', and 'nbf' claims mean?

'iat' (Issued At) indicates when the token was created, 'exp' (Expiration Time) defines when it expires, and 'nbf' (Not Before) specifies the timestamp before which the token must not be accepted.