Implementing User Authentication with JWT

Here is a token that the server in this lesson returned when alice logged in:

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxIiwidXNlcm5hbWUiOiJhbGljZSIsImlhdCI6MTc5MzU1NDU0NiwiZXhwIjoxNzkzNTU1NDQ2fQ.B41kN5hMiUPp_TVJvNWQNuuSGFVDpasohhIJaNkyWIw

It looks random, but its first two parts are plain JSON, only encoded. This lesson decodes the token, explains each part, and then builds the server that issues and checks it: alice registers, logs in, receives a token, and uses it to open her profile.