The model is a mixture-of-experts system with 2.8 trillion total parameters and 104 billion active parameters. The source reports a 1,048,576-token context window and text, image, and video inputs through the API. It lists two API model IDs: kimi-k3.1-pro and kimi-k3.1-pro-highspeed; the Highspeed variant is said to run two to three times faster.
Kimi K3.1 Pro is reported live in Kimi.ai, Kimi Work, Kimi Code, and the Kimi API. Listed API pricing is $2 per million input tokens and $10 per million output tokens, versus $3/$15 for K3. Open weights are promised for November 4, 2026, rather than reported as available now.
The source reports Moonshot's own scores of 65.7% on Terminal-Bench 4.0 and 51.7 on SWE-Marathon. It does not establish independent benchmark validation, real-world throughput, or whether the promised open-weight release will occur on schedule.