What is "jwt"

JWT (JSON WEb TOken) is a data transfer system, which allows data to be sent via URL, POST or in an HTTP header (header) in a "secure" manner. This information is digitally signed, for example signed with the HMAC algorithm, or a public/private key pair using RSA.

An example of situation that it can be used is authentication, once the user is logged in, each request that comes will include the JWT, allowing the user to continue accessing services and resources that are released with such token (Single Sign-on (SSO)).

What is and what is JWT for?