Moonshot Releases Kimi K3.1 Pro Open Weights on Hugging Face: 2.8T-Parameter, 104B-Active MoE in MXFP4 at About 1.56TB, Custom License Limits Large Model-as-a-Service Use
The official Kimi account @Kimi_Moonshot announced the Kimi K3.1 Pro model weights at 16:00 UTC on November 4; the moonshotai/Kimi-K3.1-Pro repository is public and not gated. The model card describes a natively multimodal MoE with 2.8T total and 104B active parameters and a 1M-token context, shipped as MXFP4 weights from quantization-aware training, about 1.56TB in total; vLLM, SGLang and TokenSpeed are the recommended engines. The license allows free use and modification, but Model-as-a-Service businesses with over $20M in annual revenue need a separate agreement.

Key Takeaways
- Architecture: 93 layers (1 dense), 69 KDA plus 24 Gated DSA attention layers, 896 experts with 16 selected per token plus 2 shared experts, and a 401M MoonViT-V2 vision encoder.
- Compared with K3, the full-attention Gated MLA layers are replaced with Gated DeepSeek Sparse Attention for more efficient long-context modeling.
- Vendor-reported scores on the model card: Terminal-Bench 4.0 65.7 (Opus 5.5 66.4), SWE Marathon v1.1 51.7 (Opus 5.5 46.3), HLE-Full with tools 70.0 and BrowseComp 92.1; ProgramBench 31.5 trails Opus 5.5 at 65.0.
- License: a Model-as-a-Service business with over $20M revenue in any 12 months needs a separate agreement with Moonshot, and products above 100M monthly users or $20M monthly revenue must prominently display "Kimi K3.1-Pro"; internal use is exempt from both.


