The solution is based on a Grails backend, hosted in a Cloud environment and widely uses queuing to meet scalability requirements. Queues were implemented for video encoding, antivirus scanning, mail sending, etc. Thanks to that, a client can “fire-and-forget” all long-term processes. Moreover, the REST API is stateless which also results in a scalability boost. External resources (JS, CSS) are minimized and compressed in order to optimize bandwidth usage. The front-end was built using HTML5 to provide rich user experiences and compatibility across desktop- and mobile platforms.