Gemini 3.1 Pro Preview vs Kimi K2.6
Pricing, context window and real answers (September 2026)
Gemini 3.1 Pro Preview (Google) and Kimi K2.6 (Moonshot), compared as you can actually call them on FastMetal. Both are served from the same OpenAI-compatible endpoint and API key; switching is a change to the model string.
Specs and pricing
 Gemini 3.1 Pro Preview |  Kimi K2.6 | |
|---|---|---|
| Provider | Moonshot | |
| Input (per 1M tokens) | ¥357.4 | ¥159.6 |
| Output (per 1M tokens) | ¥2,144.4 | ¥672 |
| Typical cost (1,000 in + 500 out tokens × 1,000 calls) | ¥1,430 | ¥496 |
| Context window | 1,048,576 tokens | 262,144 tokens |
| Release date | 2/19/2026 | 4/20/2026 |
| Input modalities | audio, file, image, text, video | text, image |
| Throughput (p50) | — | — |
| Arena · overall | #15 · ELO 1,487 | #52 · ELO 1,460 |
| Arena · Japanese | #9 · ELO 1,494 | #36 · ELO 1,443 |
| Arena · coding | #28 · ELO 1,520 | #39 · ELO 1,514 |
Prices are FastMetal's yen rates before tax. Arena ranks are as of the latest leaderboard scrape.
Which should you pick?
- On price, Kimi K2.6: ¥672 per 1M output tokens, 69% less than Gemini 3.1 Pro Preview.
- On the Overall arena board, Gemini 3.1 Pro Preview ranks higher (#15; Kimi K2.6 is #52).
- On the Japanese arena board, Gemini 3.1 Pro Preview ranks higher (#9; Kimi K2.6 is #36).
- On the Coding arena board, Gemini 3.1 Pro Preview ranks higher (#28; Kimi K2.6 is #39).
- For long documents, Gemini 3.1 Pro Preview: a 1,048,576-token context window against 262,144 for Kimi K2.6.
- If in doubt, try both on the same key. Switching is a change to the model string, and each is billed at its own rate.
Real answers to the same prompts
Exactly what the FastMetal gateway returned, side by side. Not benchmark scores: actual output.
Count the number of 'r's in 'strawberry'
Count the number of 'r's in 'strawberry'. Explain your reasoning step by step.
Gemini 3.1 Pro Preview
There are **3** 'r's in the word 'strawberry'.
Here is the step-by-step breakdown of the spelling:
1. **s** - not an 'r'
2. **t** - not an 'r'
3. **r** - **1st 'r'**
4. **a** - not an 'r'
5. **w** - not an 'r'
6. **b** - not an 'r'
7. **e** - not an 'r'
8. **r** - **2nd 'r'**
9. **r** - **3rd 'r'**
10. **y** - not an 'r'
Therefore, the total count is 3.
5.3s503 output tokens
Kimi K2.6
Here is the step-by-step count:
**Step 1:** Write out the word and number each letter.
1. s
2. t
3. **r** ← 1st 'r'
4. a
5. w
6. b
7. e
8. **r** ← 2nd 'r'
9. **r** ← 3rd 'r'
10. y
**Step 2:** Identify the positions containing the letter 'r'.
- The 3rd letter is **r**
- The 8th letter is **r**
- The 9th letter is **r**
**Step 3:** Tally the total.
There are **3** letter 'r's in "strawberry".
4.5s352 output tokens
Debug This Error
I'm getting the following error in my Node.js application: TypeError: Cannot read properties of undefined (reading 'map') at UserList (/app/components/UserList.js:12:25) at renderWithHooks (/app/node_modules/rea…
Gemini 3.1 Pro Preview
### The Cause
This error occurs because the `users` prop being passed to your `UserList` component is currently `undefined`.
In JavaScript, you can only use the `.map()` method on arrays. Because `users` is `undefined` (often due to data not finishing an API fetch yet, or the parent component forgetting to pass the prop), Node/React throws an error when it tries to read `.map`.
### How to Fix It
You can fix this in a few different ways, depending on how you want your application to behave.
#### Fix 1: Assign a Default Value (Recommended)
The cleanest way to handle this is to assign a default empty array to `users` in your component's parameters. If `users` is undefined, it defaults to…
13.2s1511 output tokens
Kimi K2.6
The error occurs because `users` is `undefined` when your component renders. The `.map()` method only works on arrays, so calling it on `undefined` throws this error.
This usually happens when:
- The parent component hasn't finished fetching data yet
- The `users` prop isn't being passed at all
- The prop is misspelled in the parent component
## Quick Fix
Set a **default value** for the `users` prop:
```jsx
function UserList({ users = [] }) {
return (
<ul>
{users.map(user => <li key={user.id}>{user.name}</li>)}
</ul>
);
}
```
## Alternative Fixes
**Optional chaining** (renders nothing if undefined):
```jsx
{users?.map(user => <li key={user.id}>{user.name}</li>)}
```…
71.8s864 output tokens
Code Review
Please review the following Python function and suggest improvements for readability, performance, and best practices: def get_data(url, retries=3): import requests import time for i in range(retries):…
Gemini 3.1 Pro Preview
Here is a review of your function. While the original code works, there are several areas where it can be improved regarding **best practices**, **readability**, and **performance**.
### 1. Refactored Code
Here is the improved version of your function. I will explain the specific changes below.
```python
import time
import requests
import logging
from typing import Any
# Optional: Set up a logger
logger = logging.getLogger(__name__)
def get_data(url: str, retries: int = 3, delay: int = 2, timeout: int = 10) -> list[dict[str, Any]]:
"""
Fetches JSON data from a URL and extracts active items.
Args:
url: The API endpoint to fetch data from.
retries: Number o…
23.6s3094 output tokens
Kimi K2.6
Here is a refactored version followed by a breakdown of the improvements.
### Refactored Function
```python
import logging
import time
from typing import Any
import requests
logger = logging.getLogger(__name__)
def fetch_active_items(
url: str,
*,
retries: int = 3,
timeout: float = 10.0,
backoff: float = 2.0,
) -> list[dict[str, Any]]:
"""Fetch active items from an API endpoint with retry logic.
Args:
url: The API endpoint URL.
retries: Number of retry attempts for transient failures.
timeout: HTTP request timeout in seconds.
backoff: Base delay in seconds between retries (linear backoff).
Returns:
A list of activ…
17.9s4061 output tokens
Frequently asked questions
- Which is cheaper, Gemini 3.1 Pro Preview or Kimi K2.6?
- Per 1M output tokens, Gemini 3.1 Pro Preview is ¥2,144.4 and Kimi K2.6 is ¥672 on FastMetal (yen, before tax), so Kimi K2.6 is cheaper.
- How do the context windows of Gemini 3.1 Pro Preview and Kimi K2.6 compare?
- Gemini 3.1 Pro Preview takes 1,048,576 tokens; Kimi K2.6 takes 262,144.
- Which ranks higher, Gemini 3.1 Pro Preview or Kimi K2.6?
- Gemini 3.1 Pro Preview ranks higher on the public arena (Gemini 3.1 Pro Preview #9, Kimi K2.6 #36). Ranks move as the leaderboard updates.
- Can I use Gemini 3.1 Pro Preview and Kimi K2.6 with the same API key?
- Yes. On FastMetal's OpenAI-compatible endpoint, switch by passing "gemini-3.1-pro-preview" or "kimi-k2.6" as the model. Each is billed at its own rate from the same prepaid balance.
Try both on one API key
Create an account and add credit to call Gemini 3.1 Pro Preview and Kimi K2.6 from the browser chat and the API. No monthly fee.