Remote sign-out of web based service sessions

Remote sign-out of web based service sessions. As a part of remote sign-out of web based service sessions, a user authentication token is accessed that is used to establish a web based service session and this user authentication token is stored in memory of an authentication server and returned in a cookie to the device. User access and deletion of the user authentication token from memory is accommodated using a device different from that which initially established the web based service session. Upon receipt of a browser request involving the user authentication token, it is determined whether the user authentication token is stored in memory. An access denial indication is provided to a web based service that indicates that the user authentication token is not stored in memory.