Me (Gaurav Gupta) and my co-founder on Hackr.io (Saurabh Hooda) met online and we started work in a client/vendor relationship on Lenro.co, Saurabh's original startup. I was running SquareBoat (an app/web development company based in New Delhi) and Saurabh contacted me to build Lenro.co for him.
Two years later, Saurabh decided to close it down but we had by then seen each other's style of working. So for our next startup, we just decided to do it together as co-founders.
Hackr.io is doing well and remains as one of the All-Time Top 50 Hunts on Product Hunt till date.