Meet The $9 Billion AI Company Reimagining Vibe Coding

Replit Raises $400M at a $9B Valuation | Replit Meet The $9 Billion AI Company Reimagining Vibe Coding Amjad Masad’s Replit allows users to build apps together like they’re doodling on a white board. It also made the Jordanian immigrant a billionaire along the way. Two years ago, Replit CEO Amjad Masad invited Paul Graham, the legendary cofounder of the startup incubator Y Combinator, to his home office near Palo Alto, California, to give Graham a sneak peek of Replit’s new and novel product: an AI agent that could write its own code. It was the first time Graham had seen what would become known as vibe coding. “The name hadn’t even been invented,” Graham recalls. As the agent got to work building apps, Graham, a lifelong computer programmer, instinctively looked at the code. Masad scolded him, saying there was no need, arguing that the source code would only be an unimportant byproduct, and programming would now be done in English — a radical change for software engineers. “It was mind-bending,” Graham, one of Replit’s earliest investors, tells Forbes. “He’s bald with that beard, and I think he was actually wearing a black turtleneck. I felt like he was a Bond villain: ‘Hahaha! Don’t look at that code!’” Now vibe coding, of course, is everywhere, and Replit is looking to take it a step further. On Wednesday, the startup announced its new agent, simply called Agent 4, which aims to deliver a new type of interface for vibe coding. Like last time, Masad demoed the new agent to Graham at his home office in early March. After the meeting, Graham gushed about the product on X. “Amjad showed me Replit's latest stuff,” he posted. “They're about to redefine vibe coding in a way that will seem obvious in retrospect. A lot of the biggest ideas have that quality.” Instead of just typing in prompts to instruct the agent on what to code, Replit offers what it calls a digital canvas, where users can tweak mockups and app designs, doodle drawings of new features, and colla