Chinese startup Moonshot AI has unveiled Kimi K3, a 2.8-trillion-parameter system it bills as the world’s largest open-weight AI model. The claim, made on 16 July, plants the firm squarely alongside the American frontier labs it has spent two years chasing.
The model arrives weeks after Moonshot was reported to be seeking a $30bn valuation, and it reads like a pitch to justify the figure. On the company’s own benchmarks, K3 ranks second overall behind only Anthropic’s Fable 5 and OpenAI’s GPT-5.6 Sol, the two closed models it is trying to catch.
Moonshot is best known outside China for Kimi, the consumer chat assistant that gave the startup a following among developers before it began releasing frontier-scale weights. K3 is the point at which that reputation meets the biggest model the company has shipped.
The system is a sparse mixture-of-experts design, activating roughly 50 billion of its 2.8 trillion parameters for any given token by routing through 16 of 896 experts.
The 💜 of EU techThe latest rumblings from the EU tech scene, a story from our wise ol' founder Boris, and some questionable AI art. It's free, every week, in your inbox. Sign up now!It carries a 1-million-token context window and ships with what Moonshot calls Kimi Delta Attention, a mechanism the firm says decodes up to 6.3 times faster over million-token inputs.
