The Open Green Map app has been used by map makers around the world to collect thousands of green sites over the last decade. With a new implementation, the Open Green Map has potential to truly live up to its name, and achieve a sharable, scalable, fast and easy to use application. This is what the project I will present sets out to do. Working on an open source project can sometimes make it seem like compromises around performance or user centric design are reasonable. What if you don't want to compromise in any of these 2 directions? By using an appropriate and modern tech stack, along with generative programming techniques, we hope to introduce a new approach for creating GIS applications. This talk will introduce how the new Open Green Map app works, and advantages of using DLang and Ember for a GIS app. We will also take a look at challenges that arise in relation to implementing GIS applications while having plenty of constraints around resources, and when helpful open source libraries are missing. The presentation will include an overview of the infrastructure, examples of how we generate REST APIs based on the app models and a quick look at how we efficiently display the sites on maps.