MotherDuck is a new service that connects DuckDB to the cloud. It introduces the concept of “hybrid query processing“: the ability to execute queries partly on the client and partly in the cloud. The talk covers the motivation for MotherDuck and some of its use cases; as well as the main characteristics of its system architecture, which heavily uses the extension mechanisms of DuckDB. To provide context, the talk will therefore also provide a brief overview of the DuckDB architecture.