Kimi K3 is an open-weight model rather than an open-source one, according to an analysis of Moonshot AI’s newly published license. Its checkpoint is available on Hugging Face, but the custom Kimi K3 License has no SPDX identifier and does not appear on the Open Source Initiative’s approved list.
The license generally permits use, modification, distribution, sale, deployment and fine-tuning. It requires copyright and permission notices to remain with copies. Larger commercial operators face additional terms: a model-as-a-service business with more than $20 million in revenue over any consecutive 12 months must reach a separate agreement with Moonshot AI. Commercial products exceeding 100 million monthly active users or $20 million in monthly revenue must prominently show “Kimi K3” in their interface. Internal use and access through approved providers are exempt from those two conditions.
The checkpoint is a 2.8-trillion-parameter mixture-of-experts model that activates 104 billion parameters per token. It accepts text, images and video and has a 1,048,576-token context window. Local deployment requires multi-node hardware.
OpenRouter also offers hosted access under the model ID moonshotai/kimi-k3, with reasoning controls, tool calling and structured output. Pricing and maximum output length vary by provider endpoint, and there is no free variant.