Kimi K3 is a 2.8 trillion-parameter Mixture-of-Experts model with 104 billion activated parameters per token, designed by Moonshot AI as a native multimodal foundation for long-horizon coding, knowledge work, visual understanding, and reasoning tasks. Its architecture combines Kimi Delta Attention, Attention Residuals, and Stable LatentMoE techniques, paired with a million-token context window that supports extended agentic workflows and multi-step software engineering projects. The model accepts text, image, and video inputs while producing text outputs, and is distributed with open weights under a modified MIT license, making it suitable for both commercial deployment and research use.
In practical terms, Kimi K3 is positioned for developers building agentic applications that need sustained reasoning over large codebases or document collections, with a chat completions API endpoint and broad third-party platform integrations supporting coding assistants and developer tooling. Reported benchmark performance places its coding evaluations ahead of OpenAI's GPT-5.5, reflecting Moonshot's emphasis on competitive ultra-long-context capabilities and structured-output reliability for production software workflows. Its combination of open weights, a million-token window, and tool-calling support makes it a strong fit for teams that need self-hostable frontier-class reasoning without depending on closed-provider APIs.
