Moonshot AI launches 2.8-trillion-parameter Kimi K3

Chinese AI startup Moonshot AI on Wednesday launched Kimi K3, a 2.8-trillion-parameter model that the company positions as a direct competitor to Anthropic's Claude Opus 4.8. The release makes K3 the largest open-weight model from a Chinese lab, nearly tripling the parameter count of its predecessor and arriving with a one-million-token context window.ft+2

The Financial Times London Stock Exchange Group plc reported earlier on Wednesday that the Beijing-based company was preparing to release the model "in the coming days" with between 2 trillion and 3 trillion parameters. Moonshot moved faster than anticipated: the same day, the company quietly made K3 available through its API platform and via OpenRouter, with two variants — K3·Max and K3 Cluster·Max — accessible to logged-in users.tosea+3

Architecture and Pricing

K3 is built on what Moonshot calls "Kimi Delta Attention," a hybrid linear attention mechanism that interleaves efficient linear layers with full-attention layers, allowing the model to handle its million-token context window without the memory costs that typically accompany such scale. The model also introduces a feature called "Attention Residuals," though Moonshot has not yet published technical details on the mechanism.tosea

The pricing signals a strategic shift for Moonshot, which previously competed primarily on cost. K3 is priced at $3.00 per million input tokens and $15.00 per million output tokens — roughly three to four times what its K2.6 model costs, but still 40 to 50 percent below Anthropic's Opus 4.8 and OpenAI's GPT-5.5.tosea

Closing the Gap With US Labs

The launch of K3 could challenge the prevailing industry view that Chinese AI models trail their American counterparts by eight to twelve months, according to the Financial Times. Moonshot expects K3 to match or exceed Claude Opus 4.8 on several benchmarks, though the company has not yet published official evaluation results.aiweekly+2

The timing is deliberate. The release aligns with the World Artificial Intelligence Conference 2026 in Shanghai, a venue Chinese labs have previously used for high-profile launches. Moonshot is simultaneously raising capital at a reported $31.5 billion valuation, up from $20 billion two months ago.tosea+1

However, independent verification remains absent. As of the launch, Moonshot has published no benchmark table, no technical report, and no open weights on Hugging Face — a departure from its approach with prior models like K2.6, which shipped with full documentation and open weights on day one.aiweekly+1