Is it permissible for a programmer to design a friendship and acquaintance website that focuses on open relationships (and not only marriage)?

It is not permissible to work on programming this website, because acquaintance and friendship between genders are pretexts that lead to indecency, and anything that leads to such is forbidden. Assisting in it is also forbidden, due to the generality of Allah's saying: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression."