SiteVisor is a Digital Twin based web app for environmental monitoring of buildings, with elements of asset management. At the core of the user interface is an interactive 3D viewer, rendering a building and the IoT sensors. With only a few clicks we can set up our 3D environment from scratch, by simply sketching out rooms and creating virtual sensors and configuring the data connection from their physical counterparts. The application is deployed on Kubernetes and uses Strimzi operator to run Apache Kafka cluster, which is the heart and arteries of the whole system.