Splunk provides various approaches for custom application development. It's possible to start with a so-called simple XML that provides basic functionality. XML declarations allow us to create custom input forms and even visualizations on Google Maps. When you need more, you can turn to classical application development using various languages. The earlier example explained one approach to extending existing components. With a few lines of custom code we got a simple interactive map based on data stored in Hadoop and presented as a virtual index.