Kimi K3's Weights Are Open. Its Commercial License Just Got Tighter

Moonshot AI shipped the weights for Kimi K3 this week — 2.8 trillion parameters, 1.56TB of files on Hugging Face — and OpenRouter had it live through seven providers within hours at $3 per million input tokens and $15 per million output tokens, pricing that matches Moonshot’s own API and sits squarely in frontier territory despite being freely downloadable. The benchmark numbers will get the headlines. The license is the part builders actually need to read.

What Happened

Moonshot released K3’s weights alongside serving infrastructure, continuing the open-weight release pattern it used for K2 and K2.7’s code-focused variant. But the license text changed materially between versions. K2 shipped under a “modified MIT” framing that required attribution only once a deployment crossed 100 million monthly active users or $20 million in monthly revenue — thresholds high enough that almost nobody building on K2 ever tripped them. K3 drops the “modified MIT” language entirely. Any business whose aggregate revenue exceeds $20 million over any trailing 12-month period now needs a separate commercial agreement with Moonshot before it can keep using the model. Moonshot has also stopped calling its releases “open source” in its own materials, using “open weight” consistently instead — a wording choice that signals a licensing posture, not a rights transfer.

Why It Matters

The threshold move is the story. K2’s trigger was a monthly revenue figure high enough to only catch companies operating at serious scale — the kind of business that can afford lawyers and a licensing negotiation. K3’s trigger is an annual revenue figure that a profitable mid-market SaaS company running agent products on Kimi weights could cross without ever hitting a headline-scale user base. That’s a much lower bar, and it changes who needs to be paying attention to license terms: not just the handful of companies building consumer-scale products on open weights, but any team quietly running a profitable business on top of them.

What This Means for Builders

Teams that adopted K2 assuming its terms would carry forward unchanged into future Moonshot releases need to re-read K3’s license before scaling further, not after. It’s also a preview of where open-weight licensing appears headed more broadly: as Chinese labs close the benchmark gap with US frontier models, the free-tier terms that made open weights attractive to startups are tightening in step with the models’ rising commercial value. Free download access and unrestricted commercial use are no longer the same guarantee.

Source: Simon Willison

Content created with AI assistance and reviewed for accuracy.