“Integrated Collection System (ICS): Modernization of Data Collection at Statistics Indonesia”
by Munaf, Alfatihah R. M. N. S. P.; Budi, Brilian Surya; Ashiddiiqi, Sulthoni (Statistics Indonesia)
provides a comparison of various data collection systems, including Survey Solutions, indicating that Survey Solutions is not open source. Although Survey Solutions was always free and accessible to the public since the start of its development, indeed, the source code of it was not distributed at the time that comparison study was done (in 2017).
Survey Solutions’ source code is currently available here: