Rasa

Rasa is an open-source conversational AI platform from Rasa Technologies, founded in 2016 with German roots and a remote-first organisation that maintains hubs in Berlin, Paris, London, San Francisco and Belgrade. The framework combines natural language understanding, dialogue management and the CALM (Conversational AI with Language Models) engine to blend LLM fluency with deterministic business logic, deployable on-prem or in private cloud and integrated with WhatsApp, Alexa and other channels. Rasa Open Source / Developer Edition is free; Rasa Pro is enterprise-licensed via sales (reportedly with minimum commitments around USD 35,000).