You've Been Waiting for AI Video to Generate. What If It Just Ran?

Reactor just raised $59M to make real-time AI worlds a developer primitive. Here's why that's a bigger deal than the headline.

Every generative AI product you’ve used so far works the same way. You give it instructions. It runs computations. Eventually, it hands you a result. That lag — even if it’s milliseconds — is a ceiling. It means AI can’t react. It can only respond.

A San Francisco startup called Reactor just raised $59 million to blow past that ceiling entirely.

Reactor emerged from stealth on May 28th with a Series A led by Lightspeed Venture Partners. WndrCo, Amplify Partners, Sky9 Capital, and FPV Ventures also participated. The company was co-founded by Alberto Taiuti and Bryce Schmidtchen, both former technical leads on the Apple Vision Pro. Taiuti previously co-founded Luma AI, where he built the infrastructure behind one of the most widely used 3D and video generation platforms in the market. They know what it takes to ship this stuff at scale.

The product: a unified SDK and API that lets developers build real-time interactive AI applications in just a few lines of code. No batch processing. No prompt-and-wait. The video generates as you interact with it — dynamically shaped by user input, in the moment it’s happening. Reactor calls this the shift from AI as a tool you prompt to AI as an experience you step inside.

Jeffrey Katzenberg, the Hollywood mogul turned investor, joined through his WndrCo holding company as a board observer. His read on it: “Literally every facet of the production pipeline can be enhanced using these tools. Live action, TV, film, commercial work, animation — any visual medium.” That’s not a media pitch. That’s an infrastructure pitch wearing a Hollywood jacket.