China's open weight Kimi K3 model snaps at the heels of US labs

Moonshot AI's latest open weights model shows a massive step up in size and performance.

Jul 17, 2026 10:42 AM 2 min read

China's open weight Kimi K3 model snaps at the heels of US labs — Image credit: https://unsplash.com/@danielpelaezduque

Chinese AI lab Moonshot AI is launching one of the largest open weights models yet with its 2.8 trillion-parameter Kimi K3, putting it on par with frontier counterparts.

The model was unveiled Thursday alongside benchmark data showing it is just a generation behind Anthropic and OpenAI’s leading models in most tests and on par with or ahead for some coding and agentic applications.

Moonshot said structural changes, including the use of its new Kimi Delta Attention mechanism and Attention Residuals architecture, meant Kimi K3 showed a 2.5x improvement in scaling efficiency over its predecessor, Kimi K2.

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Noah Bovenizer

Noah Bovenizer is a senior reporter with The Stack. He previously covered the transportation sector for Global Data. He has a first class degree in journalism and has also worked as a newsreader for Gaydio.