What is JWT (JSON Web Token)?
JSON Web Token (JWT) is an open standard (RFC 7519) that defines a compact and self-contained way for securely transmitting information between parties as a JSON object. This information can be verified and trusted because it is digitally signed. JWTs can be signed using a secret (with the HMAC algorithm) or a public/private key pair using RSA or ECDSA.
In its compact form, JSON Web Tokens consist of three parts separated by dots (.), which are: Header, Payload, and Signature. The **Header** typically consists of two parts: the type of the token, which is JWT, and the signing algorithm being used. The **Payload** contains the claims. Claims are statements about an entity (typically, the user) and additional data. The **Signature** is used to verify that the sender of the JWT is who it says it is and to ensure that the message wasn't changed along the way.
This tool provides a convenient way to inspect the contents of a JWT. It is important to note that decoding a JWT does not require a secret key because the information is just encoded in Base64Url format, not encrypted. Therefore, you should never store sensitive information such as passwords inside a JWT. This decoder is an essential tool for developers to debug authentication flows, check token expiration times, and verify that the correct claims are being issued by the authorization server.
Frequently Asked Questions (FAQ)
A: Ensure the token is a valid JWT string containing exactly two dots (.). Make sure there are no extra spaces or line breaks at the beginning or end of the string.
A: No, this is a read-only decoder. To modify a token, you would need to re-encode it and generate a new signature using the correct secret key.
A: Absolutely. All processing happens on your device. We do not store or transmit any part of your token to our servers.