We present an online demonstration tool illustrating a general approach to computing justifications for accepting a given decision when confronted with the preferences of several agents. Such a justification consists of a set of axioms providing a normative basis for the decision, together with a step-by-step explanation of how those axioms determine the decision. Our open-source implementation may also prove useful for realising other kinds of projects in computational social choice, particularly those requiring access to a SAT solver.