Smart IoT devices need to handle an increasing amount of data, e.g. from sensors. It does not always make sense to just send everything to the cloud. With edge computing, devices store data locally to make decisions autonomously. Thus devices can operate independently from the cloud and just be occasionally connected. But how exactly is data stored? We will look at established embedded databases like SQLite and newcomers like CrateDB and ObjectBox. What are their use cases and how can they help you to build IoT apps for the edge?