XSite is a powerful three-dimensional hydraulic fracturing numerical simulation program based on the Synthetic Rock Mass (SRM) and Lattice methods. XSite is capable of modeling multiple wellbores with multiple stages and clusters, including open-hole completions and perforation tunnels. XSite resolves general hydraulic fracture interaction, including propagation in naturally fractured reservoirs with deterministically or stochastically generated discrete fracture networks (DFNs). The models conduct fully coupled hydro-mechanical simulations. Fluid flow is simulated as fracture flow within the joint networks and as matrix flow within the intact rock.