moonshotai/Kimi-K3

2026-07-27 · Source: Simon Willison's Weblog · Field: Technology & Digital — Artificial Intelligence & Machine Learning, Emerging Technologies & Innovation, Legal & Regulatory · Depth: Intermediate, quick

Summary

Moonshot AI released the 2.8 trillion parameter Kimi K3 model weights on July 27th, 2026, available as a hefty 1.56TB download on Hugging Face. This follows their K2 model, which introduced a modified MIT license requiring attribution for large commercial entities exceeding 100 million monthly active users or \$20 million in monthly revenue. The new K3 license further deviates, explicitly requiring a separate agreement with Moonshot AI for "Model as a Service" businesses generating over \$20 million in aggregate revenue within any consecutive 12 months. Moonshot consistently labels these as "open weight" rather than "open source." OpenRouter already lists K3 from seven providers, generally matching Moonshot AI's pricing of \$3/million input and \$15/million output.

Key takeaway

For Directors of AI/ML evaluating large language models for commercial deployment, you must meticulously review the Kimi K3 license. Your "Model as a Service" business will require a separate agreement with Moonshot AI if your aggregate revenue exceeds \$20 million annually. Ensure your legal team assesses these terms to avoid compliance issues and unexpected costs, especially when considering third-party providers like OpenRouter.

Key insights

"Open weight" models like Kimi K3 increasingly impose revenue-based commercial licensing restrictions.

Principles

• "Open weight" differs from "open source" in commercial use cases.
• Licensing terms can evolve significantly between model versions.

In practice

• K3 requires a separate agreement for MaaS businesses exceeding $20M annual revenue.
• K2 required prominent attribution for large commercial products.

Topics

• Large Language Models
• Model Licensing
• Open Weight Models
• Moonshot AI
• Kimi K3
• AI Commercialization

Best for: CTO, Entrepreneur, VP of Engineering/Data, AI Engineer, Director of AI/ML, Tech Journalist

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Editorial summary, takeaway, and curation by AIssential. Original article published by Simon Willison's Weblog.