Article URL: https://simonwillison.net/2026/Jul/16/kimi-k3/ Comments URL: https://news.ycombinator.com/item?id=48947717 Points: 137 # Comments: 81

Chinese AI lab Moonshot AI announced Kimi K3 this morning, describing it as their “most capable model to date, with 2.8 trillion parameters”. It’s currently available via their website and API, but an open weight release is promised “by July 27, 2026”. Moonshot are calling this the first “open 3T-class model” (I guess they’re rounding 2.8 trillion up to 3 trillion), taking the crown from DeepSeek’s 1.6T v4 Pro. Their self-reported benchmarks have K3 mostly beating Claude Opus 4.8 max and GPT-5.5 high, while losing out to Claude Fable 5 and GPT-5.6 Sol. The model is also now the leading model on Arena.ai’s Frontend Code arena, surpassing even Claude Fable 5. The new model is notable for the pricing: $3/million input tokens and $15/million output tokens, putting it at the same level as Anthropic’s Claude Sonnet series and making it the most expensive model released by a Chinese AI lab to date. This is a significant increase on their earlier models such as Kimi K2.6 at $0.95/$4. 2.8 trillion parameters is also more than twice the size of that 1T model. I used OpenRouter (to avoid signing up for a Moonshot API key) with the llm-openrouter plugin to generate an SVG of a pelican riding a bicycle: That pelican took 95 input tokens and 16,658 output tokens (13,241 were reasoning tokens), for a total cost of 25 cents! Since K3 accepts image input I ran it against that rendered SVG above (with my alt text prompt) and got back (for 0.6 cents): Cartoon illustration of a white pelican wearing a red scarf, riding a red bicycle along a gray road with white dashed lines; the pelican has a large orange beak and webbed orange feet pedaling, with white motion lines behind it; the background shows a light blue sky with white clouds, a yellow sun, two small black birds in flight, and green grass with tiny white flowers in the foreground