Kimi K3 Fast vs Grok 4.20 Beta
moonshotai/kimi-k3-fast-api · x-ai/grok-4.20-beta
As of November 5, 2026, Grok 4.20 Beta is the cheaper API on UberLLM: $0.1750 per million input tokens and $0.3500 per million output, versus $3.55 / $17.77 for Kimi K3 Fast, about 98% less when output is 3 tokens for every input token. These are the best prices on the market right now. Both work with one OpenAI-compatible key and UberLLM adds no fee. Choose Grok 4.20 Beta to cut cost; choose Kimi K3 Fast when its capabilities fit your task better.
Kimi K3 Fast vs Grok 4.20 Beta, side by side
| Spec | Kimi K3 Fast | Grok 4.20 Beta |
|---|---|---|
| Price · input / 1M | $3.55 | $0.1750 |
| Price · output / 1M | $17.77 | $0.3500 |
| Context length | 1,000,000 | 2,000,000 |
| Max output tokens | 131,072 | 128,000 |
| Input modalities | text, image | text, image |
| Output modalities | text | text |
| Tools / functions | Yes | Yes |
| Vision (image input) | Yes | Yes |
| Reasoning | Yes | Yes |
| % off list | 21% off | 86% off |
| First token, median (7 days) | — | 4.7 s (119 requests) |
Best prices on UberLLM right now. No UberLLM fee on requests; adding credit by card costs 5.5% + $0.50. Updated November 5, 2026. A price more than 70% below list is what buyers were billed, not an error. Why so cheap?
Kimi K3 Fast vs Grok 4.20 Beta — FAQ
Is Kimi K3 Fast or Grok 4.20 Beta cheaper?
Grok 4.20 Beta is cheaper on a blended token mix, by about 98%. A request costs what its provider charged, UberLLM adds no fee, and every request is listed with its cost in Activity.
What's the price difference between Kimi K3 Fast and Grok 4.20 Beta?
Kimi K3 Fast: $3.55 in / $17.77 out per 1M tokens. Grok 4.20 Beta: $0.1750 in / $0.3500 out per 1M tokens. That's roughly a 98% blended difference. Prices are live; UberLLM adds no fee.
Can I use both Kimi K3 Fast and Grok 4.20 Beta with one API?
Yes. Both are served through a single OpenAI-compatible endpoint — set the base URL to https://api.uberllm.dev/v1 and your UberLLM key, then switch between them by changing the model id. Anthropic SDKs work via https://api.uberllm.dev/v1/messages.