Gemini 3.1 Pro Preview vs GLM 5.1
Pricing, context window and real answers (September 2026)
Gemini 3.1 Pro Preview (Google) and GLM 5.1 (Z.ai), 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 |  GLM 5.1 | |
|---|---|---|
| Provider | Z.ai | |
| Input (per 1M tokens) | ¥357.4 | ¥250.18 |
| Output (per 1M tokens) | ¥2,144.4 | ¥786.28 |
| Typical cost (1,000 in + 500 out tokens × 1,000 calls) | ¥1,430 | ¥643 |
| Context window | 1,048,576 tokens | 204,800 tokens |
| Release date | 2/19/2026 | 4/7/2026 |
| Input modalities | audio, file, image, text, video | text |
| Throughput (p50) | — | — |
| Arena · overall | #15 · ELO 1,487 | #47 · ELO 1,466 |
| Arena · Japanese | #9 · ELO 1,494 | #46 · ELO 1,434 |
| Arena · coding | #28 · ELO 1,520 | #45 · ELO 1,513 |
Prices are FastMetal's yen rates before tax. Arena ranks are as of the latest leaderboard scrape.
Which should you pick?
- On price, GLM 5.1: ¥786.28 per 1M output tokens, 63% less than Gemini 3.1 Pro Preview.
- On the Overall arena board, Gemini 3.1 Pro Preview ranks higher (#15; GLM 5.1 is #47).
- On the Japanese arena board, Gemini 3.1 Pro Preview ranks higher (#9; GLM 5.1 is #46).
- On the Coding arena board, Gemini 3.1 Pro Preview ranks higher (#28; GLM 5.1 is #45).
- For long documents, Gemini 3.1 Pro Preview: a 1,048,576-token context window against 204,800 for GLM 5.1.
- 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
GLM 5.1
There are **3** 'r's in the word "strawberry".
Here is the step-by-step reasoning:
1. Let's break down the word "strawberry" letter by letter: s - t - r - a - w - b - e - r - r - y
2. Now, let's check each letter one by one to see if it is an 'r':
- **s**: not an 'r'
- **t**: not an 'r'
- **r**: this is the 1st 'r'
- **a**: not an 'r'
- **w**: not an 'r'
- **b**: not an 'r'
- **e**: not an 'r'
- **r**: this is the 2nd 'r'
- **r**: this is the 3rd 'r'
- **y**: not an 'r'
3. Counting them up, there are three 'r's in total (in the 3rd, 8th, and 9th positions).
7.3s565 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
GLM 5.1
### What is causing the error?
The error `TypeError: Cannot read properties of undefined (reading 'map')` means you are trying to call the `.map()` method on a variable that is `undefined`.
In your code, the variable is `users`. When the `UserList` component renders, the `users` prop is `undefined`, so `undefined.map()` throws an error.
### Why is `users` undefined?
This usually happens for one of two reasons:
1. **You forgot to pass the prop:** The parent component rendering `<UserList />` is not passing the `users` attribute (e.g., `<UserList />` instead of `<UserList users={myUsers} />`).
2. **Async Data Fetching:** You are fetching the users from an API. On the initial render, befor…
45.0s1680 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
GLM 5.1
Here is a review of your function, broken down by areas for improvement, followed by a refactored version of the code.
### Key Areas for Improvement
1. **Imports Inside the Function:**
Placing `import` statements inside a function is generally discouraged in Python. It slows down the function execution every time it is called, and it violates PEP 8 (the Python style guide). Imports should always be at the top of the module.
2. **Bare `except` Clause:**
Using a bare `except:` catches *everything*, including `KeyboardInterrupt` and `SystemExit`, which makes it hard to terminate a hanging program. You should catch specific exceptions (like `requests.exceptions.RequestException`).
3. *…
70.3s2854 output tokens
Frequently asked questions
- Which is cheaper, Gemini 3.1 Pro Preview or GLM 5.1?
- Per 1M output tokens, Gemini 3.1 Pro Preview is ¥2,144.4 and GLM 5.1 is ¥786.28 on FastMetal (yen, before tax), so GLM 5.1 is cheaper.
- How do the context windows of Gemini 3.1 Pro Preview and GLM 5.1 compare?
- Gemini 3.1 Pro Preview takes 1,048,576 tokens; GLM 5.1 takes 204,800.
- Which ranks higher, Gemini 3.1 Pro Preview or GLM 5.1?
- Gemini 3.1 Pro Preview ranks higher on the public arena (Gemini 3.1 Pro Preview #9, GLM 5.1 #46). Ranks move as the leaderboard updates.
- Can I use Gemini 3.1 Pro Preview and GLM 5.1 with the same API key?
- Yes. On FastMetal's OpenAI-compatible endpoint, switch by passing "gemini-3.1-pro-preview" or "glm-5.1" 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 GLM 5.1 from the browser chat and the API. No monthly fee.