The men stumbled upon the idea in 2004 when they were students at Linköping University after a late night out resulted in a lazy Sunday morning.
"We were all sitting around in our apartment and someone suggested pizza," co-creator Erik Mellströmsom told The Local.
"Rather typically, none of us had any money, and we thought how great it would be if we could just order it online and pay with card."
Mellströmsom and his co-creators Per Anders Bjelkstål and Dan Castillo, who were all studying degrees in economics or engineering, soon realized the potential of their idea. They set to work, and gradually built up the concept until it became well-known and widely used in Linköping, central Sweden.
Their project, "Online Pizza", became an online hub where buyers can decide exactly what sort of pizza they want, order it from whichever shop that was featured online, pay by card and have it home delivered.
The idea took off, and the students soon found their hands full with a hobby that was sucking up all their spare time, and only earning them a crust, even though the student population was repeatedly coming back for seconds.
Within a few years, the trio had completed their studies and focused their attention solely on the pizza. Soon, their website (onlinepizza.se) really started bringing in the dough, and swept across Sweden.
In 2009, Mat24, another online takeaway company, wanted a slice of the company, and the two joined forces, opening sites in Poland, Austria and Finland.
But it wasn't until last Friday that the company made its biggest deal.
German food delivery company "Delivery Hero" bought Pizza Online for what Aftonbladet newspaper reported to be 250 million kronor ($37.8 million).
Mellströmsom, however, only sees this as another stepping stone.
"To be honest, this doesn't mean so much to me, our story does not end here" he told The Local.
"This just signifies the end of chapter one. We have built a successful company – that was the goal. Now we'll be in 10 different countries, featuring 19,000 restaurants," he said.
"Eventually, we want to be the best company in the world."
As for future "chapters", Mellströmsom is keen to concentrate on the current projects, but is quick to add:
"What more can you do once you're best in the world?"