Recent studies indicate tablets as the preferred devices of preschool children, due to portability, autonomy of use and variety of apps. There is also extensive evidence of the contributions of digital technologies in different areas of learning at these ages. The Aprender XXI project aimed to develop game-based learning apps, with content recommended in the Curriculum Guidelines for Pre-School Education (CGPE). The project used Design-Based Research (DBR) methodology, which combines scientific research and technological development. It was divided into three phases: preliminary study (literature review, search for existing apps, study of preschool curriculum), development (specifications, scriptwriting, design and programing) and evaluation (tests with users and conclusions). The preliminary study identified the needs to define robust apps. The evaluation with children and educator validated the development and defined improvements in the apps. As a result, we obtained four thematic apps--environment, health, citizenship and professions, composed of a set of games, suitable for autonomous use for children or for educational activities guided by educators in kindergarten. In addition, a website collects children's play data, which is represented with flowers in a virtual world, to illustrate their participation/collaboration for a better future.