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 on the trillion-parameter Mixture-of-Experts architecture.
Pricing: Input 120 credits / 1M tokens (≈ $0.60), Output 500 credits / 1M tokens (≈ $2.50).
Prices updated
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Kimi K2 Thinking API on ModelFold
Kimi K2 Thinking is Moonshot AI’s most advanced open reasoning model to date, extending the K2 series into agentic, long-horizon reasoning on the trillion-parameter Mixture-of-Experts architecture. Try Kimi K2 Thinking in the ModelFold Playground, then call it from your own code through an OpenAI-compatible chat completions API.
What Is the Kimi K2 Thinking API
Kimi K2 Thinking at a glance
Kimi K2 Thinking is a chat model from Moonshot. It accepts text as input and returns text, with a context window of up to 262K tokens.
Use it without hosting anything
On ModelFold you call Kimi K2 Thinking with a single API key — no model weights to download and no inference servers to run. The same key also works for the other chat, image, video and audio models on ModelFold.
Core Capabilities of Kimi K2 Thinking
Up to 262K tokens of context
Keep long conversations, large documents and sizeable code in a single request, so the model can reason over the full material instead of fragments.
Function calling
Kimi K2 Thinking supports tool (function) calling: describe your functions in the request and the model returns structured calls your code can run — the basis for agents and integrations.
Reasoning mode
Kimi K2 Thinking can produce reasoning before its final answer; in the Playground you can switch reasoning on or off to compare results.
Structured outputs
Ask for JSON that follows a schema (response_format), which makes extraction, classification and system integrations more reliable.
How to Use Kimi K2 Thinking on ModelFold
- 1
Step 1: Try it in the Playground
Open the Playground at the top of this page, type a prompt and see how Kimi K2 Thinking responds before writing any code.
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Step 2: Create an API key
Sign in to ModelFold and create an API key in the console. Keep it secret and send it as a Bearer token.
- 3
Step 3: Send a request
Call POST https://modelfold.ai/v1/chat/completions with "model": "kimi-k2-thinking" and your messages. Existing OpenAI-compatible SDKs work by changing the base URL and key.
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Step 4: Ship and monitor
Integrate the response into your product and check token usage and spend for every call in the console logs.
What You Can Build with Kimi K2 Thinking
Analysis and complex reasoning
Work through research questions, data interpretation, planning and other problems that need careful step-by-step reasoning.
Autonomous agents
Build agents that plan multi-step tasks, call your tools and APIs, and keep working toward a goal across long sessions.
Tool-calling backends
Route requests, call functions and chain API calls as the worker model inside larger agent systems.
AI coding assistants
Generate, explain, debug and refactor code, review pull requests and work through multi-file changes in developer tools and IDE plugins.
Frequently Asked Questions
What is 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 on the trillion-parameter Mixture-of-Experts architecture.
Which inputs does Kimi K2 Thinking support?⌄
Kimi K2 Thinking accepts text and returns text. Through ModelFold you send text messages; documents attached in the Playground are converted to text.
How long is the context window of Kimi K2 Thinking?⌄
Up to 262K tokens, shared between your input and the model’s output.
Does Kimi K2 Thinking support function calling?⌄
Yes. Kimi K2 Thinking supports tools / function calling through the standard tools parameter of the chat completions API.
How is Kimi K2 Thinking billed on ModelFold?⌄
Pay as you go by tokens: input and output tokens are charged at the per-million-token prices shown on this page. There is no monthly fee, and failed requests are not charged.
How do I call Kimi K2 Thinking through the API?⌄
Send a POST request to https://modelfold.ai/v1/chat/completions with "model": "kimi-k2-thinking", using your ModelFold API key as the Bearer token.
| Input | 120 credits 1M tokens≈ $0.60 |
| Output | 500 credits 1M tokens≈ $2.50 |
Billed per token: input and output are priced separately, and thinking tokens count as output. The Playground charges exactly the same way.
Read API docs →AI Agents · Claude Code / Cursor / Trae →curl https://modelfold.ai/v1/chat/completions \
-H "Authorization: Bearer $MODELFOLD_API_KEY" \
-H "Content-Type: application/json" \
-d '{"model":"kimi-k2-thinking","messages":[{"role":"user","content":"Hello"}]}'