Traditional monolithic applications are migrated to the cloud, typically using a microservice-like architecture. Although this migration leads to significant benefits such as scalability and development agility, it also leaves behind the transactional amenities, such as serializability, that database systems have served developers for decades. Today’s transactional cloud applications depart from these database amenities by combining aspects of state management, service messaging, and service coordination in application logic. In this talk, I will present Styx, a novel open-source dataflow-based cloud application runtime that executes scalable, low-latency transactional applications. Cloud applications in Styx can be developed as Stateful Entities: simple objects that can form arbitrary stateful function orchestrations. The Styx runtime takes care of serializable state consistency, exactly-once processing, state and event partitioning, parallelization and scaling. In this session, you will learn how Kafka, with ideas from stateful stream processing and database transactions, can be combined in order to create transactional cloud application runtimes, bringing us back to the 80s: the time when developers did not have to deploy complex technology stacks, but rather author pure business logic and trust the database for the rest.