Gemini 3.1 Pro Preview vs GPT-4.1 Nano
Pricing, context window and real answers (September 2026)
Gemini 3.1 Pro Preview (Google) and GPT-4.1 Nano (OpenAI), 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 |  GPT-4.1 Nano | |
|---|---|---|
| Provider | OpenAI | |
| Input (per 1M tokens) | ¥357.4 | ¥17.87 |
| Output (per 1M tokens) | ¥2,144.4 | ¥71.48 |
| Typical cost (1,000 in + 500 out tokens × 1,000 calls) | ¥1,430 | ¥54 |
| Context window | 1,048,576 tokens | 1,047,576 tokens |
| Release date | 2/19/2026 | 4/14/2025 |
| Input modalities | audio, file, image, text, video | image, text, file |
| Throughput (p50) | — | — |
| Arena · overall | #15 · ELO 1,487 | #243 · ELO 1,322 |
| Arena · Japanese | #9 · ELO 1,494 | #195 · ELO 1,234 |
| Arena · coding | #28 · ELO 1,520 | #226 · ELO 1,374 |
Prices are FastMetal's yen rates before tax. Arena ranks are as of the latest leaderboard scrape.
Which should you pick?
- On price, GPT-4.1 Nano: ¥71.48 per 1M output tokens, 97% less than Gemini 3.1 Pro Preview.
- On the Overall arena board, Gemini 3.1 Pro Preview ranks higher (#15; GPT-4.1 Nano is #243).
- On the Japanese arena board, Gemini 3.1 Pro Preview ranks higher (#9; GPT-4.1 Nano is #195).
- On the Coding arena board, Gemini 3.1 Pro Preview ranks higher (#28; GPT-4.1 Nano is #226).
- For long documents, Gemini 3.1 Pro Preview: a 1,048,576-token context window against 1,047,576 for GPT-4.1 Nano.
- 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
GPT-4.1 Nano
Let's analyze the word "strawberry" step by step to count the number of 'r's.
1. Write down the word: **strawberry**
2. Examine each letter one by one:
- s: no
- t: no
- r: yes (first 'r')
- a: no
- w: no
- b: no
- e: no
- r: yes (second 'r')
- r: yes (third 'r')
- y: no
3. Counting the 'r's found:
- First 'r' (at position 3)
- Second 'r' (at position 8)
- Third 'r' (at position 9)
So, there are **3** 'r's in "strawberry."
**Final answer: 3**
2.0s183 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
GPT-4.1 Nano
The error:
```
TypeError: Cannot read properties of undefined (reading 'map')
```
indicates that `users` is `undefined` at the time your `UserList` component is rendering, and you're trying to call `map` on it.
### Why is this happening?
In React, if a prop (`users` in this case) is not provided or is undefined, trying to do `users.map(...)` causes this error. This can happen if:
- The parent component does not pass `users`.
- `users` might be `null` or `undefined` initially, especially if data fetching is involved.
### How to fix it
**Option 1: Provide a default value for `users`**
Ensure that `users` defaults to an empty array if it is not provided:
```jsx
function UserList({ users…
4.3s514 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
GPT-4.1 Nano
Here's a review and an improved version of your function:
### Key improvements:
1. **Move imports to the top**: Imports should generally be at the top of the file, not inside functions.
2. **Specify exception types**: Catch specific exceptions rather than a generic `except`.
3. **Use context managers if needed**: Not necessary here, but good to consider.
4. **Avoid repeated code**: The sleep statement is the same whether there is a request exception or a non-200 status.
5. **Simplify filtering**: Use list comprehensions for clarity.
6. **Improve variable names**: For readability.
7. **Add optional headers or parameters** if needed (not required here).
8. **Optional:** Add more descriptive e…
3.4s391 output tokens
Frequently asked questions
- Which is cheaper, Gemini 3.1 Pro Preview or GPT-4.1 Nano?
- Per 1M output tokens, Gemini 3.1 Pro Preview is ¥2,144.4 and GPT-4.1 Nano is ¥71.48 on FastMetal (yen, before tax), so GPT-4.1 Nano is cheaper.
- How do the context windows of Gemini 3.1 Pro Preview and GPT-4.1 Nano compare?
- Gemini 3.1 Pro Preview takes 1,048,576 tokens; GPT-4.1 Nano takes 1,047,576.
- Which ranks higher, Gemini 3.1 Pro Preview or GPT-4.1 Nano?
- Gemini 3.1 Pro Preview ranks higher on the public arena (Gemini 3.1 Pro Preview #9, GPT-4.1 Nano #195). Ranks move as the leaderboard updates.
- Can I use Gemini 3.1 Pro Preview and GPT-4.1 Nano with the same API key?
- Yes. On FastMetal's OpenAI-compatible endpoint, switch by passing "gemini-3.1-pro-preview" or "gpt-4.1-nano" 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 GPT-4.1 Nano from the browser chat and the API. No monthly fee.