Unveiling Kimi K3: Moonshot AI’s Record-Breaking Open-Source AI Model
Today, July 27, 2026, marks a historic milestone in open-source artificial intelligence. Moonshot AI is releasing the full open weights of Kimi K3, its flagship large language model. With a staggering 2.8 trillion parameters, it stands as the largest open-weight AI model ever released to the public.
Kimi K3 first made its debut on July 16, 2026. It immediately made waves in the AI community by securing the #1 spot on the Frontend Code Arena leaderboard, surpassing Anthropic’s Claude Fable 5. The model’s unique characteristics include:
- A Mixture-of-Experts (MoE) architecture, activating 16 out of 896 specialized experts per request.
- A groundbreaking 1-million-token context window, enabling it to process entire codebases, legal archives, or book-length documents in a single pass.
Constructed on Kimi’s proprietary Delta Attention (KDA) hybrid linear attention mechanism, Kimi K3 is designed for long-horizon coding, agentic workflows, and complex knowledge work. It is now available on kimi.com, the Kimi Work desktop app, and via the Kimi API on iOS and Android. With today’s open weight release, developers worldwide can download, self-host, and fine-tune the model locally — a monumental victory for the global AI research community.
This release represents a significant comeback for Beijing-based Moonshot AI, which had seen its market share decline following DeepSeek’s disruptive rise in early 2025.
Source: VentureBeat, July 2026