{
/* Decoded Header will appear here */
}
{
/* Decoded Payload will appear here */
}
/* Signature string */
Registered Claims Inspector
RFC 7519 registered claims decoded into human-readable timestamps and localized dates:
| Claim | Description | Raw Value | Parsed / Localized Value |
|---|---|---|---|
| Paste a JWT token above to view parsed claims. | |||
Understanding JSON Web Tokens (JWT)
A JSON Web Token (JWT) is an open standard (RFC 7519) that defines a compact, URL-safe means for securely transmitting claims between parties as a JSON object. JWTs are commonly used for stateless user authentication, Single Sign-On (SSO), and secure API authorization headers in modern web applications.
1. Header (Algorithm & Type)
Typically consists of two parts: the token type (JWT) and the cryptographic signing algorithm being used, such as HMAC SHA256 (HS256) or RSA SHA256 (RS256).
2. Payload (Claims Data)
Contains user identity information and permissions. Includes standard claims like sub (subject ID), iss (issuer), aud (audience), and exp (expiration timestamp in seconds).
3. Signature (Integrity Verification)
Created by taking the encoded header, the encoded payload, a secret key, and passing them through the algorithm specified in the header to ensure that the token was not tampered with in transit.
Frequently Asked Questions (FAQ)
Is my JWT token sent over the internet or logged?
Never. TechTools processes and decodes JWTs 100% locally within your web browser using client-side JavaScript. Unlike some online decoders that send your token to external analytics or logging servers, our tool is zero-trust and completely offline-capable.
Is a JWT encrypted or just encoded?
Standard JWTs are signed and encoded with Base64URL, not encrypted. Anyone who possesses a JWT can view the header and payload data simply by decoding it. Sensitive secrets like passwords or unencrypted credit card numbers should never be stored in a standard JWT payload. If encryption is required, JWE (JSON Web Encryption) should be utilized.
How does the expiration (exp) claim work?
The exp claim represents a Unix epoch timestamp (seconds since January 1, 1970 00:00:00 UTC). When a backend service receives a request with a Bearer token, it compares the current server time with the exp timestamp. If the current time is greater than exp, the token is expired and rejected with HTTP status 401 Unauthorized.
Client-Side JWT Decoder, Token Inspector & Debugger
JSON Web Tokens (JWT) are the backbone of modern cloud authentication, single sign-on (SSO), OAuth 2.0 authorization, and microservice architectures. Whether you are building web applications, securing fintech trading platforms, or integrating API gateways, developers frequently need to inspect the contents of an access token, check claim expiration, and diagnose authentication failures. The TechTools Online JWT Decoder allows you to decode and analyze any JSON Web Token instantly in your browser with zero security risk.
How to Decode and Inspect a JWT Token
- Paste Your Encoded Token: Paste your raw JWT string (in the format
header.payload.signature) into the input editor. - Automatic Dissection: The tool automatically parses and color-codes the three distinct token components: the Header (algorithm details), the Payload (user claims and metadata), and the Signature.
- Inspect Claims & Expiration: View decoded JSON claims like
sub(subject),iss(issuer),aud(audience), androles. - Check Expiration Status: The automated timer parses the
expclaim and compares it to current time to flag whether the token is active or expired.
Key Benefits for Developers, Security Engineers & API Architects
- Strict Client-Side Privacy: Most online JWT tools transmit tokens across the internet, exposing bearer tokens to third-party interception. TechTools decodes tokens locally using pure browser JavaScript — keeping your session tokens secure.
- Real-Time Expiration Analysis: Never wonder why an API returns
401 Unauthorized. The tool translates UNIX timestamps into your local timezone and flags expired tokens immediately. - Color-Coded Token Architecture: Easily distinguish between the base64url-encoded Header, Payload, and Signature segments.
- Essential for Modern API & Microservice Workflows: Streamlines debugging for Supabase, Firebase, AWS Cognito, Auth0, Okta, and custom JWT authentication backends.