CosyncJWT is a JWT Authentication service specifically designed for MongoDB Realm application. It supports RSA public/private key third party email authentication and a number of features for onboard users to a Realm application. These features include signup and invite email confirmation, two-factor verification through the Google authenticator and SMS through Twilio, and configurable meta-data through the JWT standard. CosyncJWT offers both a cloud implementation where Cosync hosts the application/user authentication data, and will soon be releasing a self-hosted version of the service, where developers can save their user data to their own MongoDB Atlas cluster. Our talk will focus on the benefits of JWT authentication and how to easily implement CosyncJWT within a Realm application.