“We had a free trial from day one but we were in effect charging from day one. There's nothing quite like the dopamine high of realizing you're creating something valuable to the world and people are returning. You captured some of it right — it's hard to debate something is being done.”

Charge from day one — paid conversions are the only unambiguous signal

Zack insisted on real revenue from launch instead of free-tier vanity metrics. Mixpanel events can be gamed or noisy, but paid conversions are unambiguous proof of value — and the dopamine loop kept both founders building hard.