Overview
Kimi K2 Thinking is Moonshot AI's reasoning-focused model, a trillion-parameter mixture-of-experts system (32B active) with a 256K context window that generates extensive chain-of-thought for hard math, coding and science problems. Released November 2025, it posts results that would have been frontier six months earlier — ~71% SWE-bench Verified, ~83% LiveCodeBench — at API prices several times cheaper than top Western models.
Moonshot is one of China's "AI tigers," and K2 Thinking is its statement that excellent open-weight reasoning models can be trained and shipped globally. It ships under a modified MIT licence through an OpenAI-compatible API, and the blunt takeaway from independent reviewers is simple: if your spend is dominated by an expensive frontier model and you haven't benchmarked Kimi, you may be overspending.
Key capabilities
- Extensive chain-of-thought reasoning
- 1T-parameter MoE with 32B active
- 256K context window
- Open weights, OpenAI-compatible API
At a glance
SWE-bench Verified
~71%
LiveCodeBench
~83%
Price
Several× cheaper than frontier
Pricing: Very low for its capability — open weights available.
Pros & cons
What we like
- Frontier-class reasoning at low cost
- Strong agentic and coding scores
- Open weights, easy to integrate
Trade-offs
- Heavy chain-of-thought can add latency
- Named alongside peers in 2026 distillation scrutiny
The verdict
Kimi K2 Thinking is one of 2026's clearest value stories — reasoning that rivals far pricier models, with open weights and an easy API. For math, coding and agentic work on a budget, it deserves a place in every benchmark shortlist.
Best for: Reasoning, math and coding at frontier quality on a budget.
Frequently asked questions
What is Kimi K2 Thinking best at?
Deep reasoning tasks — competitive math, complex coding and multi-step problem solving — where its extensive chain-of-thought pays off, all at a fraction of frontier pricing.
Is Kimi K2 open source?
Yes. It's released under a modified MIT licence with open weights and an OpenAI-compatible API, so it's easy to self-host or integrate.
