The most interesting part of WayToday implementation is MySQL handler socket protocol used as very fast (faster than the redis access according to some reviews) way to use MySQL as NoSQL database for the updates and key searches. The traditional SQL interface is still may be used for reporting purposes. Although handler socket is not ported on the most recent versions of MySQL but we consider it as very promising solution for the problems requiring both fast transactions and powerful reporting.
Another not very trivial feature is using ZMQ as the main transport protocol between the server and mobile device and as the source of messages for websocket connections.
Pay attenion ZMQ is not the separated layer as it would be Kafka or MQTT broker but is embedded library working in the space of nodejs application.