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Moonshot AI

Kimi K3 Fast

Kimi K3 Fast is the faster serving path for Moonshot AI's Kimi K3. It trades a higher per-token rate for lower latency, keeps the context window of 1M tokens, and routes through AI Gateway via Fireworks, Morph, Wafer. Your use is subject to Moonshot AI's Terms & Privacy Policies.

ReasoningTool UseImplicit CachingFile InputVision (Image)
Use with AI GatewayView docs
import { streamText } from 'ai'


const result = streamText({
  model: 'moonshotai/kimi-k3-fast',
  prompt: 'Why is the sky blue?'
})
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Frequently Asked Questions

  • How is Kimi K3 Fast different from Kimi K3?

    Serving speed and price. Kimi K3 Fast is the faster serving path for the same model, so the context window, native visual understanding, and always-on thinking all carry over. The per-token rate is higher; compare the rates and live metrics on each model's page.

  • How do I request the fast tier?

    Two ways. Set the speed option to fast while keeping the model ID on moonshotai/kimi-k3, which falls back to standard speed when the fast tier isn't available. Or call moonshotai/kimi-k3-fast directly to pin every request to the fast tier.

  • How fast is Kimi K3 Fast?

    Speed varies with load, context length, and routing, so a single number would mislead. Check the live throughput and latency metrics on this page for measured performance through AI Gateway.

  • Does Kimi K3 Fast accept images and video?

    Yes. Text, image, and video input all work, matching the base model. Visual understanding is native, so screenshots and screen recordings feed a coding loop without a separate vision model.

  • Can I turn off thinking mode on Kimi K3 Fast?

    No. Thinking mode is always on for the Kimi K3 models, so every response includes a deliberation pass. Budget output tokens for it, and reach for a non-thinking Kimi K2 variant when deliberation doesn't help.

  • Can I keep Kimi K3 Fast inference in the United States?

    Yes. AI Gateway serves the Kimi K3 models from US-based providers, and inferenceRegion restricts a request to US data centers. Regional inference lists above the standard rate, so check the pricing panel on this page first.

  • How do I use Kimi K3 Fast on AI Gateway?

    Use the identifier moonshotai/kimi-k3-fast with the AI SDK or any supported interface like Chat Completions, Responses, or Messages. AI Gateway routes across fireworks, morph, wafer and handles failover automatically.

  • Does Kimi K3 Fast support zero data retention?

    Yes, Zero Data Retention is available for this model. Zero Data Retention is offered on a per-provider basis. See https://vercel.com/docs/ai-gateway/capabilities/zdr for details.