Agree with gnaritas. If there is no code at present, and you will be putting in as many hours as each of the others, then the starting point for your share is

Agree with gnaritas. If there is no code at present, and you will be putting in as many hours as each of the others, then the starting point for your share is 33%. From there, add or subtract percentages for relative experience. If one of the founders has tremendous experience in the field at hand, and you have great experience in coding (but not "tremendous"), then you might agree to say 20%...and so on.