LexEVS is the central EVS terminology server, developed by the Mayo Clinic with NCI and other support. LexEVS provides a common terminology model and open access to a wide range of terminologies, terminology value sets, and cross-terminology mappings needed by NCI and its partners. For users wanting to install and run a local instance of LexEVS, the LexEVS server package provides a comprehensive set of software and services to load, publish, and deploy vocabulary in a variety of web-enabled and grid environments.

The LexEVS API serves users who want programmatic access to the data made available by LexEVS. The LexBIG Java API and LexGrid model are the strategic EVS interfaces, having replaced the legacy EVS API and the EVS 3.2 model. For a summary of the components of the server package and the API, refer to the LexEVS Servers and APIs wiki page.