We know about chat bots since 1992 in IRC chats, where they were used to automate activities for a few hundred users at time. Today, through social media and messengers, they can reach about 14% of the world population. We are still at the early stages, and many product teams working all around the globe are rediscovering independently the same foundations. This talk tries to present a simple high level model for designing chat bots, so we can start having a common language and a common approach to discuss and move the conversation forward. Talk done at IxDA Meetup London.