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Kimi K3.1 Pro overview
Kimi K3.1 Pro by Moonshot AI
Kimi K3.1 Pro is Moonshot AI's most capable 3T-class open-weight model, a post-trained upgrade of Kimi K3 with a 1,048,576-token context window, reasoning, parallel tool calling, vision and structured outputs.
Kimi K3.1 Pro specs
- Model ID
moonshot/kimi-k3-1-pro- Developer
- Moonshot AI
- Context window
- 1,048,576 tokens
- Max output
- 1,048,576 tokens
- Input
- Text, Image
- Output
- Text
- API
- OpenAI-compatible, base URL
https://api.aimlapi.com/v1
What is Kimi K3.1 Pro API?
Kimi K3.1 Pro is Moonshot AI's most capable 3T-class open-weight model and the first release in the K3.1 series. It is a post-trained version of Kimi K3, trained with substantially more post-training compute, and is built for full-project coding, long-horizon agent work, research and professional knowledge work. On AI/ML API it is available through the OpenAI-compatible chat completions endpoint.
Technical specifications
- Architecture: Mixture-of-Experts, 2.8T total / 104B active parameters
- Context window: 1,048,576 tokens
- Capabilities: reasoning, tool calling (parallel), vision, structured output, streaming
- Release date: October 23, 2026
Performance benchmarks
Figures reported by Moonshot AI at launch:
- Kimi Code Bench 3.0 Long-horizon: 61.2% (Kimi K3: 55.95%)
Where to use Kimi K3.1 Pro
Full-project coding
Multi-file features, refactors and long-running engineering tasks across large repositories.
3D and game development
Moonshot AI positions the model for work in Blender, Unreal Engine, Unity, Godot and CAD tools.
Financial analysis and research
Financial modeling, document cross-referencing and investment research with long context.
Agentic workflows
Multi-step tool use where the model plans, calls tools and keeps context over long sessions.
Use cases
Kimi K3.1 Pro is built for full-project coding, including multi-file features, refactors and long-horizon engineering tasks across large repositories.
Moonshot AI positions it for 3D modeling and game development, with direct work in Blender, Unreal Engine, Unity, Godot and CAD software.
It is suited to financial modeling, investment research and other knowledge work that requires cross-referencing many documents in a single context.
With reasoning, parallel tool calling and a 1M-token context window, it fits agentic workflows that run many steps with minimal supervision.
Capabilities
- Reasoning
- Function calling
- Vision
- Structured outputs
- Streaming
Kimi K3.1 Pro benchmarks by 
Artificial Analysis
See how Kimi K3.1 Pro compares in intelligence, generation speed, cost per task and latency. Data retrieved Nov 3, 2026.
Benchmark results
Compare 7 models available on AI/ML API across 4 independent benchmarks.
Humanity's Last Exam
Expert-written questions across academic subjects.
Terminal-Bench 4.0
Agentic tasks completed in a command-line environment.
AA-LCR
Reasoning across long documents of about 100k tokens.
SciCode
Python coding tasks drawn from scientific research.
Kimi K3.1 Pro API pricing
| Usage | Price | Unit |
|---|---|---|
| Input | $2 | 1M tokens |
| Output | $10 | 1M tokens |
| Cached input | $0.2 | 1M tokens |
Prices from the AI/ML API price list, checked on Nov 4, 2026.
Kimi K3.1 Pro vs other models: token prices
AI/ML API input and output rates for 5 models, per million tokens.
| Model | Input | Output |
|---|---|---|
 Kimi K3.1 Pro | $2 | $10 |
| Kimi K2.7 Code | $0.95 | $4 |
| Kimi K2.7 Code HighSpeed | $1.9 | $8 |
| Kimi K3 | $3 | $15 |
| Kimi K3.1 Pro Highspeed | $4 | $20 |
How to use the Kimi K3.1 Pro API
View docs
Build with your agent
Give your agent the model details, code and documentation.
Paste it into your coding agent to build the integration.
1Get your API key
Create API keyexport AIMLAPI_KEY="8f2b4c7d9a1e6b3f…"2Make your first request
curl 'https://api.aimlapi.com/v1/chat/completions' \
-H "Authorization: Bearer $AIMLAPI_KEY" \
-H 'Content-Type: application/json' \
-d '{
"model": "moonshot/kimi-k3-1-pro",
"messages": [
{
"role": "user",
"content": "Write a haiku about the ocean."
}
]
}'import os
import requests
headers = {
"Authorization": f"Bearer {os.environ['AIMLAPI_KEY']}",
"Content-Type": "application/json",
}
payload = {
"model": "moonshot/kimi-k3-1-pro",
"messages": [
{
"role": "user",
"content": "Write a haiku about the ocean."
}
]
}
response = requests.post("https://api.aimlapi.com/v1/chat/completions", headers=headers, json=payload, timeout=120)
response.raise_for_status()
print(response.json())const response = await fetch("https://api.aimlapi.com/v1/chat/completions", {
method: "POST",
headers: {
Authorization: `Bearer ${process.env.AIMLAPI_KEY}`,
"Content-Type": "application/json",
},
body: JSON.stringify({
"model": "moonshot/kimi-k3-1-pro",
"messages": [
{
"role": "user",
"content": "Write a haiku about the ocean."
}
]
}),
});
if (!response.ok) throw new Error(`HTTP ${response.status}`);
console.log(await response.json());Models similar to Kimi K3.1 Pro
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Kimi K3.1 Pro FAQ
What is Kimi K3.1 Pro?
Kimi K3.1 Pro is Moonshot AI's most capable 3T-class open-weight model and the first model in the K3.1 series. It is a post-trained version of Kimi K3, built for coding, research and agentic tool use, with a 1,048,576-token context window.
What inputs and outputs does Kimi K3.1 Pro support?
Kimi K3.1 Pro takes text and image input and returns text. It supports reasoning, tool calling (including parallel tool calls), vision, structured output and streaming.
What is the context window of Kimi K3.1 Pro?
Kimi K3.1 Pro has a 1,048,576-token context window, enough to keep large codebases, long documents and multi-step agent sessions in a single request.
How much does Kimi K3.1 Pro cost on AI/ML API?
Kimi K3.1 Pro costs $2 per 1M input tokens, $0.20 per 1M cached input tokens and $10 per 1M output tokens. Reasoning tokens are billed at the output rate.
How is Kimi K3.1 Pro different from Kimi K3?
Kimi K3.1 Pro keeps the Kimi K3 architecture (2.8T total / 104B active parameters, 1M context) and adds substantially more post-training. Moonshot AI reports gains in long-horizon coding (61.2% vs 55.95% on Kimi Code Bench 3.0 Long-horizon), financial modeling and research, and a lower price than Kimi K3.
How do I call Kimi K3.1 Pro via API?
Send a request to the OpenAI-compatible chat completions endpoint https://api.aimlapi.com/v1/chat/completions with the model ID moonshot/kimi-k3-1-pro and your AI/ML API key.
What is the Kimi K3.1 Pro model ID?
Use moonshot/kimi-k3-1-pro as the model parameter. Requests go to the OpenAI-compatible endpoint with your AI/ML API key.