Our Mathematical Programming Modulo Theories (MPMT) constraint solving framework extends Mathematical Programming technology with techniques from the field of Automated Reasoning, e.g., solvers for first-order theories. In previous work, we used MPMT to synthesize system architectures for Boeing’s Dreamliner and we studied the theoretical aspects of MPMT by means of the Branch and Cut Modulo T (BC(T)) transition system. BC(T) can be thought of as a blueprint for MPMT solvers. This paper provides a more practical and algorithmic view of BC(T). We elaborate on the design and features of Inez, our BC(T) constraint solver. Inez is an open-source, freely available superset of the OCaml programming language that uses the SCIP Branch and Cut framework to extend OCaml with MPMT capability. Inez allows users to write programs that arbitrarily interweave general computation with MPMT constraint solving.