Decode JSON Web Tokens (JWT) Privately & Securely
Inspect header algorithms, token payload claims, expiration timestamps, and issuer details instantly. Zero server transit guarantees your secrets remain completely private.
How to Decode a JWT Token
Inspect header algorithms, token payload claims, expiration timestamps, and issuer details instantly. Zero server transit guarantees your secrets remain completely private.
Paste JWT String
Paste your raw encoded JSON Web Token (e.g., eyJhbGciOi...) into the token input area.
Instant In-Browser Parsing
Our client-side engine splits the three token sections (Header, Payload, Signature) instantly.
Review Claims & Expiration
Inspect beautified JSON claims, user roles, issue dates (iat), and token expiration status (exp).
Copy Parsed Payload
Copy your formatted payload JSON or individual claim values with one click for debugging.
Why Decode JWTs with Khalasna?
100% Client-Side Privacy
Your production authentication tokens and sensitive claims never leave your device.
Expiration & Time Ticker
Automatically evaluates the 'exp' claim to display whether the token is currently active or expired.
Color-Coded Token Structure
Distinct color highlighting separating Header (red), Payload (purple), and Signature (cyan).
JSON Claims Beautification
Formats nested payload objects with clean indentation for effortless inspection.
Technical Architecture: RFC 7519 Base64URL Deserialization & Claims Evaluation
A JSON Web Token (JWT) conforms to the RFC 7519 open standard, compacting security claims into three Base64URL-encoded segments separated by periods (.): Header.Payload.Signature. The Header specifies the cryptographic signing algorithm (such as HS256, RS256, or ES256). The Payload encapsulates custom claims alongside standard registered claims: iss (issuer), sub (subject), aud (audience), exp (expiration time), nbf (not before), and iat (issued at). Khalasna executes JWT decoding client-side without transmitting credentials over external networks. The engine splits the string across '.' delimiters, applies Base64URL normalization (substituting '-' with '+', '_' with '/', and appending '=' padding), decodes binary octets into UTF-8 strings via TextDecoder, and evaluates JSON.parse(). It compares the numeric exp timestamp against Date.now() / 1000 to compute exact human-readable expiration countdowns. All parsing executes purely in transient browser memory.
Popular Applications for JWT Decoding
Debugging OAuth & OpenID Connect
Inspect ID tokens and access tokens issued by Auth0, Okta, Firebase, and AWS Cognito.
Verifying User Roles & Scopes
Check permissions, claims, and role-based access control (RBAC) arrays embedded in session tokens.
Investigating Expired Sessions
Verify token issue times (iat) and expiration thresholds (exp) to troubleshoot premature user logouts.
Frequently Asked Questions
Is it safe to paste my production JWT token here?
+
Is it safe to paste my production JWT token here?
+Yes, 100% safe. Decoding runs entirely inside your browser using client-side JavaScript. Your token is never transmitted over the internet or logged on servers.
Can this tool verify the signature of my JWT?
+
Can this tool verify the signature of my JWT?
+This tool decodes the header and payload claims. Cryptographic signature verification requires providing your server's private secret or public key, which we intentionally avoid to keep your secrets private.
Why is my JWT token divided into three colors?
+
Why is my JWT token divided into three colors?
+JWTs have three parts: Header (algorithm), Payload (data claims), and Signature (cryptographic verification), color-coded for visual clarity.
How does the tool know if a token is expired?
+
How does the tool know if a token is expired?
+It checks the 'exp' claim in the payload against your computer's current time to determine if the token has expired.
Is this JWT decoder free to use?
+
Is this JWT decoder free to use?
+Yes, it is completely free with no usage limits or sign-up requirements.