What is the ruling on engaging in online transactions whose terms stipulate referring disputes to non-Islamic courts or to courts that do not apply God's law?

It is not permissible to seek judgment from other than the law of Allah, as this is a requirement of faith. Rulers must rule by what Allah has revealed, and the subjects must seek judgment from it. Faith cannot coexist with seeking judgment from other than what Allah has revealed. Whoever does not rule by what Allah has revealed is a disbeliever, an oppressor, and a transgressor. It is obligatory to rule by what Allah has revealed and to seek judgment from it in all matters of dispute, for Islam is a whole that cannot be divided. Whoever contravenes this has cast off the yoke of Islam. Therefore, seeking judgment from man-made laws, customs, and ignorant traditions is forbidden, as it is seeking judgment from the Taghut ( طاغوت - false deity/tyrant) which we were commanded to disbelieve in. Hence, any condition that refers disputed matters to a court to be resolved according to man-made law is void, and it is not permissible for a Muslim to accept it.