The core of the QSopt software is formed by the QSopt Callable Library. It provides functions for creating, manipulating, and solving LP problems. The library is written in the (ANSI) C programming language. An alpha version is available for the Java programming language. The C function library has been ported to various LINUX /UNIX platforms, to Windows 98/ME/NT/2000/XP and Windows/Cygwin. It is made available to programmers as a header file and a link library.

A graphical user interface is available on Windows 98/ME/NT/2000/XP and as an Applet anywhere. These interfaces allow users to interactively define, edit, and solve linear programming problems. Problems may be read from and written to files. Both interfaces accept problem definitions in LP and MPS format, two industry standards.

On all platforms QSopt includes a stand-alone solver, which is used as a command-line tool. The solver reads problems in LP or MPS format from files and solves these. It can be parameterized to apply the primal or dual simplex with different pricing strategies.