Kimi K2 Thinking
Kimi K2 Thinking is Moonshot AI’s most advanced open reasoning model to date, extending the K2 series into agentic, long-horizon reasoning. Built on the trillion-parameter Mixture-of-Experts (MoE) architecture introduced in Kimi K2, it activates 32 billion parameters per forward pass and supports 256 k-token context windows. The model is optimized for persistent step-by-step thought, dynamic tool invocation, and complex reasoning workflows that span hundreds of turns. It interleaves step-by-step
Context window
This model accepts 262K tokens in one request (~197K words of text).
What fits in one request
- FitsShort documentAbout 1,500 words of text
- FitsLong documentAbout 37K words of text
- FitsSmall codebaseAbout 150K words of text
- Won't fitFull novelAbout 375K words of text
Specifications
Context size, pricing, and release info in one place.
- Context window
- 262,144 tokens (262K)
- Max output tokens
- 262,144 tokens (262K)
- Speed tier
- deep
- Provider
- Moonshot
- Release date
- Nov 2025
- Input cost
- $0.600/M / 1M tokens
- Output cost
- $2.50/M / 1M tokens
Capabilities
See which features this model supports, such as vision, tools, and streaming.
- Tool use
- Can call external tools and APIs
- Supported
- Function calling
- Structured function call interface
- Supported
- Extended thinking
- Shows its chain-of-thought reasoning
- Supported
- Streaming
- Returns tokens as they are generated
- Supported
- Prompt caching
- Reuse repeated prompt prefixes cheaply
- Supported
- Vision
- Accepts image inputs alongside text
- Not supported
- Web search
- Can browse the web during a request
- Not supported
- Batch API
- Process many requests asynchronously
- Not supported
Best for
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Compare Kimi K2 Thinking
Open a side-by-side comparison with one click.
- Kimi K2 Thinking vs Amazon Titan Text Express
Kimi K2 Thinking has 524% larger context window
- Kimi K2 Thinking vs Amazon Titan Text Lite
Kimi K2 Thinking has 524% larger context window
- Kimi K2 Thinking vs Amazon Titan Text Premier
Kimi K2 Thinking has 524% larger context window
- Kimi K2 Thinking vs Claude Instant
Kimi K2 Thinking has 162% larger context window
- Kimi K2 Thinking vs Anthropic Claude
Kimi K2 Thinking has 162% larger context window
- Kimi K2 Thinking vs Codellama 34b Instruct
Kimi K2 Thinking has 6300% larger context window
Frequently asked questions
Short answers about context size and how this model behaves.
More from Moonshot
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