An equal split is a good way to start. You should then convert that into shares and agree a share price (aka valuation). Ongoing contributions in terms of hurt

An equal split is a good way to start. You should then convert that into shares and agree a share price (aka valuation). Ongoing contributions in terms of hurt money or good will (eg: programming time) can then be converted into new share issues. That's how we did it and it worked very well.