If you've worked with any modern authentication system — OAuth, Firebase Auth, Auth0, a custom login flow — you've run into a JWT. It looks like meaningless noise at first glance: three chunks of random-looking text separated by dots. It's not random at all, and you don't need a library to read...
Source: [Dev.to](https://dev.to/hamza_8cfcc811f53ea1b3a0c/how-to-decode-a-jwt-token-and-what-the-claims-actually-mean-3gm1)