Worth mentioning is that JWT is used in the OpenID Connect standard, which is built on top of OAuth 2) for the authentication part. We use it in https://userbin.com to smoothly transfer user sessions between different platforms. Previously we used to roll our own (de-)serialization, signing, session expiration and encryption schemes, but JWT solves a lot of pain and makes it more obvious for developers to understand how this part of our authentication flow works, and are able to use the JWT libraries available in most programming languages.