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Gemini 3.8 Flash vs Kimi K3.1 Pro

Side-by-side pricing per provider, context window, benchmark scores and speed, all on one OpenAI-compatible API.

Estimate monthly cost for these models
Metric
Gemini 3.8 FlashGooglegoogle/gemini-3.8-flash
Kimi K3.1 ProMoonshotAImoonshotai/kimi-k3.1-pro
Creator
Google
MoonshotAI
Released
Sep 2, 2026
Oct 23, 2026
Context window
1.05M
1.05M
Max output
66K
1.05M (best)
Input / 1MLowest provider price
$0.75 (best)
$2.00
Output / 1MLowest provider price
$3.75 (best)
$10.00
Providers
2 (best)
1
IntelligenceArtificial Analysis index
30.5
46.0 (best)
Accepts
Text, Image, Audio, Video, Files
Text, Image
Produces
Text
Text
Tool calling
Yes
Yes
Structured output
No
Yes
Reasoning
No
No

Gemini 3.8 Flash vs Kimi K3.1 Pro: summary

Gemini 3.8 Flash and Kimi K3.1 Pro are both available through FastRouter's OpenAI-compatible API, so switching between them is a change of model id, not a new integration.

Gemini 3.8 Flash, from Google, has a 1,048,576-token context window, costs from $0.75/1M input and $3.75/1M output tokens across 2 providers and scores 30.5 on the Artificial Analysis Intelligence Index.

Kimi K3.1 Pro, from MoonshotAI, has a 1,048,576-token context window, costs $2.00/1M input and $10.00/1M output tokens and scores 46.0 on the Artificial Analysis Intelligence Index.

Gemini 3.8 Flash is the cheapest on input, 2.7× cheaper than the next model and Kimi K3.1 Pro scores highest for intelligence.

Switch with one line

client = OpenAI(base_url="https://api.fastrouter.ai/api/v1", api_key="<FASTROUTER_API_KEY>") client.chat.completions.create(model="google/gemini-3.8-flash", messages=[...]) # or client.chat.completions.create(model="moonshotai/kimi-k3.1-pro", messages=[...])
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Benchmark scores sourced from ArtificialAnalysis