Decode JWT tokens instantly. View header, payload, and signature. Validate expiration and claims.
JWT (JSON Web Token) is a compact, URL-safe means of representing claims to be transferred between two parties. This decoder tool helps you inspect the contents of any JWT token instantly in your browser. No data is sent to any server – everything happens locally for maximum security and privacy.
Simply paste your JWT token into the input field above, and the tool will automatically decode the header, payload, and signature sections. It also checks common claims like expiration time, issuer, and subject to help you understand what the token contains.
1. Paste your JWT: Copy and paste your JWT token into the text area. A valid JWT consists of three parts separated by dots: header, payload, and signature.
2. Click Decode: The tool will split the token and decode the Base64Url-encoded parts into readable JSON format.
3. Review the results: Examine the decoded header to see the algorithm and type. Check the payload for claims like expiration (exp), issuer (iss), subject (sub), and custom data.
4. Validate token: The tool automatically checks if the token has expired and identifies common claims. Note that signature verification requires the secret key used to sign the token.
JWT payloads contain claims — key-value pairs that convey information about the token. Here are the most common registered claims you'll encounter:
JWT (JSON Web Token) is an open standard (RFC 7519) that defines a compact and self-contained way for securely transmitting information between parties as a JSON object. It's commonly used for authentication and authorization in web applications.
Yes, absolutely. All decoding happens in your browser using JavaScript. No token data is ever sent to any server. Your JWT information remains completely private and secure.
No, signature verification requires the secret key that was used to sign the token. This tool only decodes and displays the JWT contents. To verify signatures, you need access to the issuer's secret key.
A JWT consists of three parts: Header (contains metadata like algorithm and type), Payload (contains claims like expiration, issuer, and custom data), and Signature (used to verify the token's authenticity).
The "exp" (expiration time) claim identifies the expiration time on or after which the JWT must not be accepted for processing. It's represented as a Unix timestamp (seconds since January 1, 1970 UTC).
Yes, this JWT decoder is completely free to use. No registration or account is required. Use it as often as you need for debugging, development, or learning purposes.