We have been working on creating a new version of Azavea's REX real estate application. The new version will improve upon the existing functionality in REX by using newer mapping technology, leveraging Azavea's DecisionTree geoprocessing engine to perform weighted calculations based on user preferences, and making user-interface changes to improve usability. The research will also have a strong emphasis on exploring best-practices for client-side web development, including: standards-based design; use of javascript frameworks such as jQuery; efficient, scalable CSS design; and client-side performance.