Refer to the LexEVS wiki for detailed information including documentation, development documents, and support.


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. NCI's servers are very widely used within NCI and throughout the biomedical community.

LexEVS Server Package

The open source LexEVS server software has been deployed at a number of other sites (refer to EVS Use and Collaborations). 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 components are explained in the LexEVS 6.x Installation Guide and the LexEVS 6.x Administration Guide and summarized here.

The LexEVS local runtime package has flexible database deployment alternatives to use depending on the underlying database management system. For MySQL and PostGres the user can deploy terminologies contained in a single database or in multiple databases. Some database management software, like Oracle, requires the single data base configuration. Single database configurations allow the user to manage databases more effectively. Multiple database configurations provide a little more transparency to the underlying terminology load.

The LexEVS Administrative GUI may be installed with full-fledged loading, managing and query functions for administrators, or with query-only type interfaces for users. The tool allows for changing the LexEVS environment, including performing most administrative functions that are available in the LexEVS API. The LexEVS 6.x Administration Guide covers administrative commands, and the LexEVS 6.0 Programmer's Guide explains the rest of the commands.


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 underpinning the LexEVS server.

The LexEVS API client distributions contain the Java programs to establish a connection with distributed LexEVS services through SOAP, QBE, REST, Java, or caGrid runtime services. Dependency jars are provided which include the other open source projects required by the LexEVS clients.

LexEVS Development and Releases

LexEVS 6.0 was based on the draft standard Common Terminology Services Release 2 (CTS 2) specification. LexEVS 6.0 provides the core CTS2 functionality important to most users, including Administration, Search and Query, Mapping Support, Value Set Support and Authoring and Maintenance. LexEVS 6.1 will provide enhanced REST and other interfaces built on the final CTS2 specification, as well as improvements to search, value set and loading functionality (see LexEVS 6.1 Release Notes).

Refer to the LexEVS Release Roadmap for more information on LexEVS releases. Files from versions 5.1 and earlier are made available for download from the EVS Archives. Note that the 4.x and 5.x license terms still apply.