Kimi K3 API: price, context window and how to call it

Kimi K3 is Moonshot AI's flagship model for software engineering, knowledge work and long, multi-step agent tasks. AIFans API serves it through OpenAI- and Anthropic-compatible endpoints, so the OpenAI SDKs, Claude Code and most AI tools can call it by changing the base URL, the key and the model name to kimi-k3.

Price

• Pay as you go per token, no subscription and no minimum spend. Failed calls are never billed.
• Kimi K3 reasons before it answers; that thinking is billed as output tokens, so give max_tokens room (1000 or more).
• Online top-ups carry a payment processing fee of 5.5% (minimum $0.8), added at checkout and shown before you pay; it is not part of your credit.

What it can do

• A context window of about 1 million tokens: whole repositories and long documents fit.
• Native image understanding, alongside text.
• Reasoning (thinking) and structured output; prompt caching makes repeated context cheaper (the cached-input price above).

Why call it here

• One key for Kimi K3 and the other models on the models page: switch by changing the model name.
• Every call is itemised in the console with its tokens and price, with daily, monthly and total spending caps per key.
• Servers in Singapore, close to Southeast Asia, India and East Asia.

Call it with the OpenAI SDK

# pip install openai
from openai import OpenAI

client = OpenAI(api_key="YOUR_API_KEY", base_url="https://api.aifans.fan/v1")
resp = client.chat.completions.create(
    model="kimi-k3",
    messages=[{"role": "user", "content": "Hello"}],
    max_tokens=1000,
)
print(resp.choices[0].message.content)

Use it in Claude Code

Put this in ~/.claude/settings.json; the Claude Code guide has the details.

{
  "env": {
    "ANTHROPIC_BASE_URL": "https://api.aifans.fan",
    "ANTHROPIC_AUTH_TOKEN": "YOUR_API_KEY",
    "ANTHROPIC_MODEL": "kimi-k3",
    "ANTHROPIC_DEFAULT_OPUS_MODEL": "kimi-k3",
    "ANTHROPIC_DEFAULT_SONNET_MODEL": "kimi-k3",
    "ANTHROPIC_DEFAULT_HAIKU_MODEL": "kimi-k3",
    "CLAUDE_CODE_SUBAGENT_MODEL": "kimi-k3"
  }
}