He was, and still is.

You are correct about the risk. They aren't our only customer but are the largest one. If they left, we would continue to be profitable, but just barely. :)

Regarding conflict of interest, he has handled it well. Like me with my own boss, he was transparent with his boss from day one, and is very good about defending his employer's interests with anything related to PriceTable. We have actually given his company a pretty great deal in terms of pricing — and that's because he negotiated like hell with me, his cofounder, on their behalf!

Regardless, that's why I'm anxious to expand our client base, because it would greatly reduce the risk of having most of our eggs in this one client's basket.

Depending on local laws and your cofounder‘s contract, there may also be a risk that his employer could claim ownership of the software.

Maybe risky if the client company finds out the CTO has been moonlighting, but there are risks worth taking. Many times, this is one of them.

Building a SaaS product without a first customer is, to me, riskier, so I say well done.

Hard to launch a biz without risk in some front