Binary population-synthesis codes are fundamental tools for studying the evolution of large samples of stars and binaries.
They can be used for a large variety of purposes, from populating cosmological simulations with realistic stellar populations to studying rare and peculiar objects such as progenitors of binary compact objects (black holes and neutron stars). Their role is also crucial in making predictions for next-generation instruments (e.g. LISA/Einstein Telescope). In this talk, we will give a brief overview of the different population synthesis codes available nowadays and their peculiarities and differences. In particular, we will present a new fully revised version of the population synthesis code SEVN (Stellar EVolution for N-body codes, Iorio et al., 2023). SEVN is currently the only publicly available population synthesis code that is flexible enough to allow the exploration of different stellar evolution models. We will show its
application to study the demography of binary compact objects and confront our results with those which use past stellar-evolution prescriptions. Finally, we will conclude our talk by discussing the improvements required to enhance the modelling and predictive capabilities of population synthesis codes.
