We use JWT for doing time and ip address limited cross domain redirection. We also use it for partners who want to provide sso access to our site with having to implement a full oAuth. They just provide us with their public key and use any of a number of libraries for to generate a JWT with the ip address and an short expiration and an email. Once we receive a JWT key and validate it using their public key (and other associated fields) we establish a standard cookie session.