Open Source VistA Platform

The complete Open Source VistA stack consists of:

GNU/Linux
The combination of the GNU tools, Open Source M such as GT.M and YottaDB and the Linux kernel, and VistA which together provide a robust, scalable open source stack of software.

VistA
Veterans Health Information Systems and Technology Architecture, a Healthcare Information System (HIS). VistA is widely believed to be the largest integrated HIS in the world. It was originally developed and maintained by the U.S. Department of Veterans Affairs, based on the systems software architecture and implementation methodology developed by the U.S. Public Health Service jointly with the National Bureau of Standards. It is designed to provide a high-quality medical care environment for the country's military veterans. VistA has a proven track record of supporting a large variety of clinical settings and medical delivery systems.  VistA is in production today at hundreds of healthcare facilities across the country from small outpatient clinics to large medical centers. This software and  derivatives of this software are currently used by the Indian Health Service and a number of other healthcare organizations around the world.

GT.M & YottaDB
GT.M is an implementation of the Standard M programming system (M = MUMPS = Massachusetts General Hospital Utility Multi-Programming System). VistA is written in Standard M. GT.M is an implementation of M from Fidelity Information Services. GT.M on the x86 GNU / Linux platform has been released as open source for use on Linux and YottaDB has enhanced that code base, which is still open source,  It can be downloaded from  and can be downloaded from https://yottadb.com/

WorldVistA recommends the use of open source software and open standards, beyond the HIS stack.

We are deeply grateful to Source Forge for providing us with our place in cyberspace for releasing WorldVistA EHR.