We present the open-source C++ library FireFly for the
reconstruction of multivariate rational functions over finite fields. We
discuss the involved algorithms and their implementation. As an application, we
use FireFly in the context of integration-by-parts reductions and
compare runtime and memory consumption to a fully algebraic approach with the
program Kira.Comment: 46 pages, 3 figures, 6 tables; v2: matches published versio