What Is Kimi K3? Complete 2026 Guide to Moonshot AI's Open Source Model

Short summary

Kimi K3 is Moonshot AI's 2.8T-parameter open-source MoE model with a 1M-token context window, released July 2026. It uses a hybrid KDA linear attention + MLA full attention architecture to achieve long context efficiently, and benchmarks competitively with Claude and GPT on software engineering tasks at a fraction of the cost. The guide covers architecture, benchmarks, and how to start using the model via web app, API, or open weights.

• •2.8T-param open-source MoE model with 1M-token context from Moonshot AI
• •Hybrid linear/full attention architecture reduces serving costs for long contexts
• •Beats or matches Claude and GPT on coding benchmarks at significantly lower cost per task

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