The FLOWer code solves the three-dimensional compressible Reynolds-averaged Navier-Stokes equations in integral form in the subsonic, transonic and supersonic flow regime. Turbulence is modeled by either algebraic or two-equation transport models. The code is adapted to the simulation of exterior flow fields around complex configurations. Since a rotating reference frame can be used, FLOWer is also applicable to propellers and rotors.