Kimi K3 is now fully open, but bigger companies face a licensing catch

Key points

• Moonshot AI released the full downloadable model weights for Kimi K3, its largest AI model, in June 2025.
• Kimi K3 contains 2.8 trillion parameters and supports a one-million-token context window, the technology that determines how much text the model can read at once.
• Companies running AI-as-a-service businesses with combined annual revenue above $20 million must negotiate a separate commercial deal with Moonshot before using the model.
• Products with more than 100 million monthly active users, or more than $20 million in monthly revenue, must display the "Kimi K3" name visibly in their interface.
• Internal use, meaning deployments that never expose the model to outside users, is fully exempt from both restrictions.

Moonshot AI, a Chinese startup best known for its Kimi family of AI models, released the full model weights for Kimi K3 this week. Model weights are the actual trained files you need to run an AI model on your own hardware, without sending data to anyone else's servers. The release also includes a 47-page technical report and the supporting code needed to deploy the system independently.

Kimi K3 is a large language model, the same category of technology that powers ChatGPT and Claude, built using a design called Mixture-of-Experts. That architecture keeps costs down by activating only a portion of the model's capacity at any given moment: of 896 specialist sub-networks, 104 activate per request. The full model holds 2.8 trillion parameters, the numerical values learned during training that shape how the model responds.

VentureBeat reported on the model's API debut earlier this month, before the weights were public.

What does the licence actually say?

For most users, the terms are generous. Researchers, individual developers and smaller businesses can download, modify and build commercial products with Kimi K3 at no cost.

Two clauses change the picture for larger organisations.

Clause 2 targets companies running what the licence calls a "Model as a Service" business, meaning any company that lets outside customers send inputs to the model and get outputs back, such as through an API. If that company, together with any related businesses under the same parent, earns more than $20 million in total revenue over any 12-month period, it must sign a separate commercial agreement with Moonshot AI before using Kimi K3.

The threshold covers total company revenue, not just revenue from Kimi K3 products. A subsidiary of a large corporation could trigger the requirement even if the subsidiary itself is small.

Clause 3 adds a branding obligation. Once a product built on Kimi K3 exceeds 100 million monthly active users, or $20 million in monthly revenue, the product must show the words "Kimi K3" prominently in its interface. For consumer apps and enterprise software that typically keep their underlying AI invisible, that is a real constraint.

Who is actually affected?

Internal tools are fully exempt. A company using Kimi K3 as a private employee assistant for writing, research or data work has no extra obligations, because clause 4 carves out any use that never reaches third parties.

Startups and independent developers are largely unaffected by clauses 2 and 3. The restrictions bite only when a company is both selling AI-access-as-a-service and clearing the revenue bar.

AI researcher Nathan Lambert, a former co-lead on the open-model project at AI startup Ai2, described the licence on social media as "inspired by MIT but distinctly non-commercial" for companies above the threshold. His summary matched the broader developer reaction: praise for the openness of the release, caution about the commercial terms.

What should your business do?

If your organisation runs a platform that lets customers query an AI model directly, check whether your group's combined annual revenue crosses $20 million. If it does, contact Moonshot AI before deploying Kimi K3 commercially. If you are building a consumer product, plan for the attribution requirement at scale. If Kimi K3 would only run inside your own office systems, you can proceed without any additional agreement.

Common questions

Can a small startup use Kimi K3 for free in a commercial product?

Yes. The commercial restrictions in clauses 2 and 3 apply only to Model-as-a-Service operators above the $20 million annual revenue threshold. Startups below that level, or those building end-user products rather than selling raw model access, face no extra obligations.

Does "open weights" mean the same thing as open source?

Not always. Open weights means the trained model files are publicly available to download and run. Open source typically means the code carries a permissive licence, such as MIT or Apache 2.0, with no restrictions on commercial use. Kimi K3's licence sits between the two: freer than a closed API, but with added conditions for large commercial operators.