Moonshot AI releases Kimi K3 to challenge U.S. frontier models

Moonshot AI released Kimi K3, a 2.8-trillion-parameter model it describes as the world’s largest open-source AI model. The Beijing-based startup, backed by Alibaba, is positioning the system against leading proprietary models from Anthropic and OpenAI, with full weights scheduled for release on July 27. K3 includes a 1-million-token context window, native visual understanding and an always-on reasoning mode called thinking mode.

The model uses Moonshot’s Kimi Delta Attention and Attention Residuals architectures, and its API is compatible with the OpenAI SDK. Pricing is set at $3 per million input tokens and $15 per million output tokens, with cached input tokens at $0.30 per million. Benchmarks cited in the release show K3 near the top of several leaderboards, including a 91.2 out of 100 score on BrowseComp and first-place results in multiple real-world task automation tests.

Moonshot also highlighted K3’s agent capabilities through a 48 hours autonomous chip design demonstration using open-source electronic design automation tools. The company said the model produced a 4 square millimeters functional chip design that reached 100 MHz and could decode more than 8,700 tokens per second in simulation. The launch marks a comeback attempt after DeepSeek’s rise weakened Moonshot’s market position, and it underscores China’s growing push to build global influence through open-source AI models.