[iforgotmypass]

I'm a development team lead / senior engineer who's sometimes assuming the role of CTO for young companies. From my experience, the best way to approach this is: * Express the work required in money (as you would with any contractor - determine the market value of the work involved) * Multiply this value a few times (coefficient more or less is a subjective evaluation of the risks not succeeding) * Calculate the possible profits after 1-2 years of running business (how much of that money you will be able or willing to pay out in dividends?) * Equity share should be as big as to allow receiving the amount of money obtained in the second step

For example - let's assume that building your MVP and maintaining it for 6 months until you're able to cover maintenance and improvement costs, would cost you around 30 000 $. Then let's multiply it by 3 or 4 and get around 100 000 $. Let's say you're certain that you will be able to pay out 500 000 $ in dividends in the second year. That amounts to about 20% equity share.

Also, it would be very good to give cash as well. Depending on the amount of the equity share - 20-50% of the market value for the job involved.