Kimi K3 is the first open model in the 3-trillion-parameter class.

Moonshot released it July 16: 2.8T parameters, MoE routing 896 experts with 16 active per token, native multimodal input, 1M-token context, with full open weights promised by July 27. Model overview here. It ships MXFP4 (4-bit float with per-block scaling) from day one, putting the full weight footprint around 1.4 TB rather than the ~5.6 TB bf16 would need. API pricing is $3.00/M input on cache miss, $0.30 on hit, $15.00/M output. The quantization choice is what makes self-hosting even theoretically discussable at this scale, and I'd bet that was the point.