Alan Nichol co-founded Rasa in December 2016. Rasa began life as an open source NLU for chatbots and has expanded to other features, including voice interactivity. The company raised $13 million in venture funding in 2019 and came back about twelve months later with a $26 million funding round in 2020 after showing strong growth numbers in both open source downloads and new enterprise clients.  Nichol is CTO at Rasa and before that was co-founder and CTO of a Techstars-backed productivity startup that had a conversational angle. He earned a PhD in Engineering from Cambridge with a machine learning focus. He also has an advanced degree in chemical physics from the University of Edinburgh. Today, we talk about the conversational AI stack, chatbots, voice, open source, and where we are headed with custom assistants.