In mid-September 2023, Rami Ismail was at his home in the Netherlands when his phone began to buzz, buzz and buzz again. Ismail, a videogame developer who'd become well known for a hit iPhone game, Ridiculous Fishing, often received unsolicited messages from other indie designers, but even so, this was an unusually intense flurry of activity.

Every message asked a variation of the same question: "Have you seen what Unity has done?"

Ismail had spent the past few years as an advisor to fellow developers around the world, counseling them on how they might replicate the life-changing success he had enjoyed. Like Ismail, many of them had built their games using Unity, the game engine that today powers many of the smallest and largest games alike.

Videogame engines—the software used to build games—do not typically inspire passion or anguish, but Unity was different. The co-founders had established the business with a vision that was simple, ambitious and laudable: to democratize game development by making professional-grade tools available to everyone. Working from their native Denmark, they released the first version of their software in 2005, and Unity became one of the first game engines to support the iPhone, making it a go-to tool for mobile developers just as the App Store boom began. As a result, Unity was a darling among tech investors, backed by Silver Lake, Thrive Capital and Sequoia Capital. (Sequoia chief Roelof Boetha still sits on Unity's board.)