Kimi K3
Moonshot's 2.8-trillion-parameter model, the largest open weights ever released, under a custom revenue-gated license.
Overview
Moonshot AI announced Kimi K3 on July 16, 2026, with weights following on July 27, 2026, at 2.8 trillion parameters -- the largest open-weights model released to date. It debuted at #3 on the Artificial Analysis leaderboard behind Claude Fable 5 and GPT-5.6 Sol, but led on Arena.ai's front-end web development benchmark. Weights are released under a custom license requiring companies with more than $20M in annual revenue to negotiate a contract with Moonshot before offering K3 to external customers as a service. On October 23, 2026 Moonshot released Kimi K3.1 Pro, a post-trained K3 with substantially more post-training compute and a 1M-token context window, plus a K3.1 Pro Highspeed variant that runs 2-3x faster (API IDs kimi-k3.1-pro and kimi-k3.1-pro-highspeed). Moonshot self-reports 65.7% on Terminal-Bench 4.0 (Claude Opus 5.5 66.4%, GPT-6 Astra 58.2%), 61.2% on Kimi Code Bench 3.0 (K3: 55.95%), 81.0% on xdev-bench-hard (K3: 33.3%) and claim-level hallucination down from 23.4% to 8.3%. It is available on Kimi.ai, the Kimi apps, Kimi Work 3.1.0+, Kimi Code and the Kimi API; cyber-related data was removed from mid-training and RL ahead of the open-weight release, and the launch post lists no pricing. As of November 8, 2026 the K3.1 Pro weights are on Hugging Face as moonshotai/Kimi-K3.1-Pro (2.8T total parameters, 104B active per token, 1,048,576-token context, custom Kimi K3.1 Pro License); one secondary report dates the weights release to November 4, 2026, matching Moonshot's promised date, but the model card itself carries no date.
This is a sourced directory entry. Features and capabilities are reported in the linked sources; this entry does not document independent Aymorphic testing.
Key features
- 2.8 trillion parameters (largest open-weights model to date)
- #3 on the Artificial Analysis leaderboard at launch
- Leads Arena.ai's front-end web development benchmark
- Custom license: revenue-gated commercial-service terms above $20M/year
- Kimi K3.1 Pro (Oct 23, 2026): 1M context, self-reported 65.7% Terminal-Bench 4.0 and 8.3% claim-level hallucination (K3: 23.4%)
- Kimi K3.1 Pro Highspeed: 2-3x faster variant
- Kimi K3.1 Pro open weights on Hugging Face: 104B active parameters per token, 1,048,576-token context, Kimi K3.1 Pro License
Use cases
- Front-end and web development agentic coding
- General frontier-class reasoning at open-weight cost
Pricing
Weights free for most uses; commercial service resale requires a negotiated contract above $20M annual revenue.
Pricing reflects the source record and may change. Confirm current terms with the provider.
Dates and sources
- Released
- 16 Jul 2026
- Record updated
- 8 Nov 2026
- Record last checked
- 8 Nov 2026