[imalex]

We built everything by hand. Cordova is our glue to the native side, but React is what really makes the chat stuff tick.

As for the Ruby/JSON stuff, that was also built by hand (actually the very first thing we built before we even had the UI in place). Whenever a conversation is started, the client gets the entire syntax tree from the server and evaluates it to make the conversation happen. We actually thought that pushing the state to the client actually made things easier since the server no longer has to manage the status of many concurrent conversations. It also means faster responses in poor network conditions.

I think the main reason for chatbot platforms to push things to the server is out of necessity because they work across many clients (Messenger, etc) where they don't control the client, and because they may be doing some heavy lifting with NLP that can only be done on the server.