The design of SCIP is based on the notion of constraints. It supports about 20 constraint types for mixed-integer linear programming, mixed-integer nonlinear programming, mixed-integer all-quadratic programming and Pseudo-Boolean  optimization. There are also some global CP constraints available.
Run as a standalone solver, it is one of the fastest non-commercial solvers for mixed integer programs. SCIP can be accessed through the modeling system of GAMS. Interfaces to MATLAB and AMPL are available within the standard distribution.