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Moonshot AI · Language Model

Kimi K2

Moonshot's open-weight trillion-parameter base model.

4.2Released 20251T MoE (32B active)

Overview

Kimi K2 is Moonshot AI's open-weight base model — a 1-trillion-parameter mixture-of-experts system with 32B active parameters that powers the Kimi assistant. It pairs strong general capability with the long context and tool use that make it a practical backbone for agents, and it's the foundation the reasoning-focused K2 Thinking variant builds on.

As an open-weight model under a modified MIT licence, K2 gives developers direct access to weights and an OpenAI-compatible API at low cost. For workloads that don't need heavy chain-of-thought, the base K2 is faster and cheaper than the Thinking variant while still delivering competitive quality.

Key capabilities

  • 1T-parameter MoE base model
  • Long context and solid tool use
  • Open weights, low cost
  • Foundation for K2 Thinking

At a glance

Params

1T total / 32B active

Licence

Modified MIT (open weights)

Pricing: Low — open weights and cheap API.

Pros & cons

What we like

  • Strong general-purpose open model
  • Faster/cheaper than the Thinking variant
  • Easy to self-host

Trade-offs

  • Less deep reasoning than K2 Thinking
  • Newer flagship variants exist

The verdict

4.2Aggregate review

Kimi K2 is a capable, affordable open-weight generalist and a great default when you don't need K2 Thinking's heavy reasoning. For agents and high-volume work on open weights, it's an easy model to recommend.

Best for: General-purpose open-weight assistant and agent workloads.

Frequently asked questions

Should I use Kimi K2 or K2 Thinking?

Use base K2 for fast, cheap general tasks; switch to K2 Thinking when a problem needs deep, multi-step reasoning.

Further reading

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