DECO is a web-based framework for the interior decoration, which successfully merges Real-Time Communication, Web3D and Semantic Web technologies. The interior design concepts of the system are based on an OWL ontology which is hosted by Apache Jena Semantic Framework,while a SPARQL questionnaire with specific number of questions regarding to various parameters of the room space is filled by the users. The display of the appropriate decoration solutions was succeeded with the assistance of WebRTC protocol as the realtime communication mean and an X3DOM scene as the graphical layout according to their ontological descriptors. Moreover, the implemented GUI not only supports an automatic visual reconstruction of a design scheme in users’ browser, but it also allows them to modify the scene according to their desires. Also, we implement our own MCU server for multi-party video call, which is written in JavaScript language. Our approach enables WebRTC-based video and audio conferencing.