JWT Standard Guide: How to Securely Decode and Parse JSON Web Tokens
Learn how to examine JSON Web Tokens (JWT), understand their three-part structure, and verify their security claims locally.
JWT Standard Guide: How to Securely Decode and Parse JSON Web Tokens
In modern web development, JSON Web Tokens (JWT) are the dominant standard for managing user sessions and authentication in APIs and microservices. They allow servers to verify a client's identity without needing to constantly query session databases.
Anatomy of a JWT
A JWT token consists of three parts separated by periods (`.`):
- Header: Contains the type of token and the signing algorithm used (e.g. HS256 or RS256).
- Payload (Body): Contains the claims or claims, which are user data (such as ID, role and expiration time `exp`).
- Signature: The cryptographic hash of the header and payload combined with a secret key from the server.
It is crucial to remember that the first two parts are simply Base64Url encoded, so they are readable by anyone.
To inspect the content and expiration dates of your tokens securely and locally, you can use our decoder:
Instantly decode your tokens to verify their claims, verify signatures and analyze their structure without sending any data over the internet.
