Kimi K3.1 Pro
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Kimi K3.1 Pro — Moonshot AI's 3T-class open-weight flagship for coding, 3D creation and financial research, with a 1M-token context.
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- Context window
- 1M
- Max output
- 1M
- Input modalities
- TextImage
- Output modalities
- Text
- Capabilities
- Vision · Reasoning · Tool calling · Coding · Prompt cache · Paid cache writes
- Upstream release
- 2026-10-23
- RouteMux name
- moonshot/kimi-k3.1-pro
What is Kimi K3.1 Pro
Kimi K3.1 Pro is the first model in Moonshot AI's K3.1 series, released on October 23, 2026. Built on Kimi K3's 3T-class Mixture-of-Experts architecture, it adds large-scale joint reinforcement learning across hundreds of domains, with targeted gains in coding, 3D creation (Blender, FreeCAD, Unreal Engine and Godot) and financial research. Moonshot reports 61.2% on Kimi Code Bench 3.0 Long-horizon (up from 55.95% on K3), 65.7% on Terminal-Bench 4.0 and 64.4 on the OfficeQA Pro v2 financial document benchmark; on Kimi Hallu Bench Hard, claim-level hallucination drops from 23.4% on K3 to 8.3%, and the share of responses containing at least one factual error falls to 42.4% of K3's rate.
The context window is 1M tokens (1,048,576), and max_completion_tokens defaults to 131072 and can be raised up to 1048576. Vision is native, and on RouteMux it accepts text and image input. Reasoning is always on and cannot be disabled; you set its depth with the top-level reasoning_effort field, which accepts low, high and max and defaults to max. Moonshot's parameter rules still apply: temperature 1.0, top_p 0.95, n 1 and both penalties at 0 are fixed, and sending other values returns an error, so leave them out of the request; in multi-turn chats and tool calls, return the full assistant message unchanged, including reasoning_content; and tool_choice accepts auto, none and required. It is callable over OpenAI Chat Completions, OpenAI Responses and Anthropic Messages.
Against Kimi K3: both share the 1M context window, 1,048,576 output ceiling and reasoning_effort levels, while K3.1 Pro adds cross-domain joint reinforcement learning for stronger long-horizon coding, 3D modeling and financial analysis with fewer hallucinations. Stay on kimi-k3 only when existing prompts or evaluation baselines are pinned to the July 2026 K3 release. Moonshot has also announced that the K2 series (including kimi-k2.7-code) will retire at the end of December 2026 and recommends migrating to kimi-k3.1-pro.
On RouteMux, Kimi K3.1 Pro costs $1.6 per 1M input tokens (official $2) and $8 per 1M output tokens (official $10), with cached input at $0.16 per 1M, 20% below the official price.
Kimi K3.1 Pro API pricing
Prices verified 2026-11-11
Cache read $0.16/M · Cache write $1.6/M
Estimate cost
Key capabilities
- Joint RL post-training
- Post-trained on Kimi K3 across hundreds of domains, reaching 61.2% on Kimi Code Bench 3.0 Long-horizon.
- 1M context, up to 1M output
max_completion_tokensdefaults to 131072 and goes up to 1048576.- Much lower hallucination rate
- Claim-level hallucination on Kimi Hallu Bench Hard drops from 23.4% on K3 to 8.3%.
- Three effort levels & vision
- Reasoning is always on with
reasoning_effortlow, high or max (default max), plus native image input. - Three protocols
- OpenAI Chat, OpenAI Responses, and Anthropic Messages all route to this model.
Common use cases
- Long-horizon coding & 3D creation
- Moonshot highlights full-stack engineering alongside 3D scene and asset generation in Blender, FreeCAD, Unreal Engine and Godot.
- Financial research & filings
- Scores 64.4 on OfficeQA Pro v2 for financial document analysis, suited for long filings, research reports and data extraction.
- Fact-critical deep research
- With claim-level hallucinations cut to 8.3% on Kimi Hallu Bench Hard, it fits research workflows that demand strict factual grounding.
Limited time10% extra Credits on your first top-up — up to 200 bonus Credits
Applies to your first top-up within 72 hours of signing up. Minimum $20, once per account.
Interface and protocols
Use any of these IDs to call this model via the API.
moonshot/kimi-k3.1-proReplace the ROUTEMUX_KEY placeholder with your API key. Create one →
from openai import OpenAI
client = OpenAI(
base_url="https://api.routemux.com/v1",
api_key="<ROUTEMUX_KEY>",
)
completion = client.chat.completions.create(
model="moonshot/kimi-k3.1-pro",
messages=[{"role": "user", "content": "What is the meaning of life?"}],
)
print(completion.choices[0].message.content)Performance (last 30 days)
Kimi K3.1 Pro FAQ
›What is Kimi K3.1 Pro?
Kimi K3.1 Pro — Moonshot AI's 3T-class open-weight flagship for coding, 3D creation and financial research, with a 1M-token context.
›How large is the context window of Kimi K3.1 Pro?
Kimi K3.1 Pro supports a context window of up to 1M tokens, with up to 1M output tokens per request.
›How much does the Kimi K3.1 Pro API cost?
Through RouteMux, Kimi K3.1 Pro costs $1.6 for input and $8 for output (USD per 1M tokens), below the official list price.
›How do I call Kimi K3.1 Pro via API?
Kimi K3.1 Pro is OpenAI-compatible: point your base URL at RouteMux and set the model field to moonshot/kimi-k3.1-pro — no code changes needed.
›Which input and output modalities does Kimi K3.1 Pro support?
Kimi K3.1 Pro accepts text, image as input and produces text as output.
›When was Kimi K3.1 Pro released?
Kimi K3.1 Pro was released on October 23, 2026.