Uday Ruddarraju, the Indian-origin tech leader who played a key role in developing xAI’s supercomputer Colossus, has officially joined OpenAI, marking a high-profile shift in the AI industry. Ruddarraju spent just over a year at xAI, Elon Musk’s artificial intelligence venture, where he helped design and scale Colossus, a system powered by over 200,000 GPUs and central to training Grok 3, one of xAI’s flagship models.

In a farewell message posted on X, Ruddarraju expressed appreciation for the opportunity to work under Musk and be part of a mission that pushed the limits of AI compute infrastructure. “Jensen Huang was right — Elon and his teams are singular in what they can achieve,” he wrote, referencing Nvidia’s CEO. He also called working directly under Musk “the best part” of his time at xAI.

His transition to OpenAI was confirmed shortly after, with OpenAI co-founder Greg Brockman welcoming him in an internal company message later made public. Ruddarraju acknowledged the move by reposting the announcement and writing, “Excited to join you, Greg Brockman!”

Ruddarraju is one of four notable additions to OpenAI’s team. Joining him are David Lau, a former senior software leader at Tesla; Mike Dalton, who previously worked at both xAI and Robinhood; and Angela Fan, an AI researcher from Meta. These hires bring significant expertise in AI systems, large-scale infrastructure, and machine learning innovation.

At OpenAI, Ruddarraju is expected to contribute to Stargate, a next-generation infrastructure initiative designed to support future iterations of the company’s advanced AI models. Speaking to Wiredhe described Stargate as “a high-stakes infrastructure challenge that aligns well with the kind of ambitious work” he’s passionate about.

The move underscores ongoing talent competition among top AI firms, as companies like OpenAI, xAI, and Meta race to build more powerful systems to support the rapidly evolving demands of artificial intelligence development.