Kimi K2 Thinking
VerifiedHandles extended text reasoning with a 256k-token context window.
About Kimi K2 Thinking
Kimi K2 Thinking was developed by Moonshot AI as a proprietary LLM. Its architecture supports a context length of 262144 tokens while accepting only text input. The model is not released as open weights and lists no specific parameter count.
The large context capacity allows the model to process and reason over lengthy documents or multi-turn conversations without truncation. This design reduces the need for chunking or summarization steps that smaller-context models often require.
Users typically apply Kimi K2 Thinking to tasks such as long-form document analysis, code review across large repositories, and maintaining coherence in extended dialogues. Its closed nature means access occurs through Moonshot AI's hosted service rather than local deployment.
Capabilities
How Kimi K2 Thinking compares
Kimi K2 Thinking (striped bar) vs other language models on intelligence, speed and price.
Price
USD per 1M output tokens · Lower is better · Kimi K2 Thinking ranks #63 of 78
Sources: Artificial Analysis (intelligence, speed) · OpenRouter (price).
Best for
Long document analysis
The model excels at processing and synthesizing information from documents up to its full context length in a single pass.
Complex mathematical proofs
It supports detailed step-by-step logical reasoning for advanced math and logic problems.
Extended coding sessions
The model handles multi-turn code generation, debugging, and analysis across large codebases.
Strengths & limitations
Strengths
- +Strong performance on very long inputs
- +Coherent reasoning across large contexts
- +Effective at maintaining thread in long conversations
Limitations
- –Text-only (no vision or multimodal input)
- –Reasoning quality can degrade on extremely long or noisy contexts
- –No real-time knowledge beyond training cutoff
Cost calculator
Estimate what Kimi K2 Thinking would cost for your usage.
Based on Kimi K2 Thinking's $0.60/1M input · $2.50/1M output. Estimate only — actual cost varies by provider and caching.
Quick start
OpenRouter's API is OpenAI-compatible — most SDKs work by just swapping the base URL. Only the model slug changes between models.
import OpenAI from "openai";
const client = new OpenAI({
baseURL: "https://openrouter.ai/api/v1",
apiKey: process.env.OPENROUTER_API_KEY,
});
const completion = await client.chat.completions.create({
model: "moonshotai/kimi-k2-thinking",
messages: [{ role: "user", content: "Hello!" }],
});
console.log(completion.choices[0].message.content);Model slug: moonshotai/kimi-k2-thinking
Editor's verdict
Kimi K2 Thinking is Moonshot AI's proprietary language models with a 262K-token context window.
At $2.50 per 1M output tokens, it is mid-priced for its class.
It is available through Moonshot AI's API and aggregators like OpenRouter.
Best suited to strong performance on very long inputs and coherent reasoning across large contexts.
Frequently asked questions
Pricing details are available directly from Moonshot AI.
User reviews
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