Who Is Uday Ruddarraju? Indian-Origin Engineer Who Quit Elon Musk’s xAI To Join OpenAI | Tech News

Last Updated:July 12, 2025, 19:24 IST

Ruddarraju, head of infrastructure engineering at Elon Musk’s xAI, resigned after a year. He built Colossus, a supercomputer with 250,000 GPUs, and trained Grok 3

Uday Ruddarraju, the Indian‑origin head of infrastructure engineering at Elon Musk’s AI startup xAI. (Image via X/@udayruddarraju)

Uday Ruddarraju, the Indian‑origin head of infrastructure engineering at Elon Musk’s AI startup xAI, has announced his resignation, marking the end of a landmark year in which he helped build one of the world’s most powerful AI systems.

At xAI, Ruddarraju spearheaded the creation of Colossus, a supercomputer housing over 250,000 GPUs—one of the largest such systems ever built. He also led the training of Grok 3, the company’s latest AI model, overseeing the largest pre‑training run known to date across 100,000 GPUs.

Who Is Uday Ruddarraju?

Uday Ruddarraju completed a master’s degree in computer science at the University of Minnesota before taking up engineering roles at eBay and Robinhood.

In June 2024, he joined xAI and X (formerly Twitter) as Head of Infrastructure Engineering. His remit was vast—covering compute, networking, storage, data platforms, production systems, research tools, and data‑centre back‑office operations.

Architect Of Colossus And Grok 3

At xAI, his role included building and operating large-scale AI systems, modernising core infrastructure for both xAI and X to boost reliability and developer productivity, streamlining CI/CD pipelines for faster deployment, and debugging performance issues to ensure stable, long-duration training cycles.

On 8 July, Ruddarraju announced his departure from xAI through posts on X and LinkedIn. Reflecting on his time at the company, he described the experience as “unforgettable” and confirmed that his last day had already passed.

“When I first joined, I thought everyone was absolutely nuts for thinking we could deploy 100K GPUs in 4 months, especially without a fully functioning site. Watching us go and double that and most importantly successfully train Grok 3 made me incredibly proud… and very happy to be wrong,” he wrote.

Ruddarraju also noted that building Colossus and training Grok 3 were among the highlights of his career and moments he would always remember. “Special thanks to everyone on the infrastructure team who met impossible expectations and the entire research team for your partnership throughout. You’re the best! I am certain building Colossus and training Grok 3 are definitely highlights of my career I will remember forever.”

In his message, Ruddarraju also referenced Nvidia CEO Jensen Huang, saying he was right in his praise of Elon Musk and his teams. He described them as “singular in what they can achieve” and expressed gratitude for having played a small part in shaping the future of AI infrastructure from the inside. He ended his note by hinting at future plans, saying he was “excited for what’s next.”

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