It depends on your country/jurisdiction. Most countries I worked in, anything done after hours, not using company resources, and not in the competition space o

It depends on your country/jurisdiction. Most countries I worked in, anything done after hours, not using company resources, and not in the competition space of the employer is simply allowed. No company would be able to enforce that. In fact (I have had that happen) if the contract tries to over reach, in particular regarding IP, then that clause could just be made void in court.