  Luminosity monitoring at $e^+e^-$ colliders is investigated using SANC Monte
Carlo event generator ReneSANCe and integrator MCSANC for simulation of Bhabha
scattering at low angles. Results are presented for center-of-mass energies of
the Z boson resonance and 240 GeV for the conditions of typical luminosity
detectors. It is shown that taking into account bremsstrahlung events with
extremely low electron scattering angles is relevant to match the precision
tags of the future electron-positron colliders.
