If you are only paying him equity and no salary, he is a co-founder. How much equity he gets depends on what each of you bring to the table and on the negotiati

If you are only paying him equity and no salary, he is a co-founder. How much equity he gets depends on what each of you bring to the table and on the negotiations with him. Google "founder equity calculator" to get a good idea of what factors to think of. Those calculators are not perfect, but make for a good starting point.