According to the API documentation (http://developers.viber.com/api/rest-bot-api/index.html#viber-rest-api), there are not many functions available. I would like to clarify is there a way to get the history of messages using the API?
Update Because of this API is designed for creating bots, is there an approach to writing custom Viber clients? For instance, Telegram has API for this purpose: https://core.telegram.org/methods