The National Institute of Health (NIH) launches the RADx Radical research collaboratives (RADx-rad) to advance new, non-traditional approaches for COVID-19 testing. RADxrad projects are required to adopt common data elements (CDEs) to collect data to increase data interoperability. To overcome the challenges in finding appropriate CDEs for a wide range of study variables, we create a web application -IMI-CDE to ease the burden of mapping study variables to CDEs from researchers. IMI-CDE can automatically recommend CDE candidates for a study variable based on its name and description. Together with interactive mapping interfaces, IMI-CDE allows researchers to perform variable-CDE mapping with one mouse click. In addition, the IMI-CDE application supports users with multiple roles to work collaboratively on the mapping tasks. We have piloted the IMI-CDE with RADx-rad projects. 22 researchers from 8 different projects have started to use the IMI-CDE system for variable-CDE mappings. The beta-testing evaluators reported the system is intuitive, effective, and easy to use.