Moonshot AI has unveiled Kimi K3, a 2.8-trillion-parameter open source AI model that claims frontier-level performance against top proprietary rivals, marking another major step in China’s open AI race.
Moonshot AI has unveiled Kimi K3, claiming it is the world’s largest open source artificial intelligence (AI) model with 2.8 trillion parameters, surpassing previous Chinese open models including DeepSeek V4 Pro (1.6 trillion parameters) and Zhipu AI’s GLM-5 series (744 billion parameters). The company described K3 as achieving “open frontier intelligence” while targeting long-horizon coding, knowledge work and complex reasoning.
According to Moonshot AI, K3 consistently outperformed OpenAI’s GPT-5.5, Anthropic’s Claude Opus 4.8 and Zhipu AI’s GLM-5.2 across multiple evaluations. On self-reported benchmarks, it also exceeded Anthropic’s Claude Fable 5 and OpenAI’s GPT-5.6 Sol in Program Bench and SWE Marathon, which assess end-to-end software development and ultra-long-horizon software engineering.
K3 also topped Arena.AI’s Fronted Code Arena across brand & marketing, reference-based design, data & analytics, consumer product, and simulations & content creation tools, trailing Claude Fable 5 only in gaming.
Independent benchmarking firm Artificial Analysis gave K3 an Intelligence Index score of 57, placing it alongside Claude Opus 4.8 and GPT-5.5, although still behind Claude Fable 5 and GPT-5.6 Sol overall. The firm also noted K3’s higher pricing than most Chinese open-weight peers, with an estimated task cost of US$0.94.
Kimi K3 is available through Moonshot’s chatbot, Kimi Work, Kimi Code and API platform, with full model weights scheduled for release on July 27, reinforcing the company’s open source strategy amid intensifying AI competition between Chinese and US developers.
