GLM 5.1 vs Solar Pro 4
Pricing, context window and real answers (August 2026)
GLM 5.1 (Z.ai) and Solar Pro 4 (Upstage), 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
 GLM 5.1 | Solar Pro 4 | |
|---|---|---|
| Provider | Z.ai | Upstage |
| Input (per 1M tokens) | ¥250.18 | ¥5.28 |
| Output (per 1M tokens) | ¥786.28 | ¥21.11 |
| Typical cost (1,000 in + 500 out tokens × 1,000 calls) | ¥643 | ¥16 |
| Context window | 204,800 tokens | 524,288 tokens |
| Release date | 4/7/2026 | 8/10/2026 |
| Input modalities | text | text |
| Arena · overall | #41 · ELO 1,466 | #173 · ELO 1,376 |
| Arena · Japanese | #49 · ELO 1,430 | Unranked |
| Arena · coding | #36 · ELO 1,514 | #140 · ELO 1,448 |
Prices are FastMetal's yen rates before tax. Arena ranks are as of the latest leaderboard scrape.
Which should you pick?
- On price, Solar Pro 4: ¥21.11 per 1M output tokens, 97% less than GLM 5.1.
- On the Overall arena board, GLM 5.1 ranks higher (#41; Solar Pro 4 is #173).
- On the Coding arena board, GLM 5.1 ranks higher (#36; Solar Pro 4 is #140).
- For long documents, Solar Pro 4: a 524,288-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.
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
Solar Pro 4
The word "strawberry" contains **3** 'r's. Here's the step-by-step breakdown:
1. **Spell out the word explicitly** to isolate each letter:
`s - t - r - a - w - b - e - r - r - y`
2. **Scan through the letters in order** and count every instance of the lowercase letter `r`:
- `s` → 0
- `t` → 0
- `r` → **1**
- `a` → 0
- `w` → 0
- `b` → 0
- `e` → 0
- `r` → **2**
- `r` → **3**
- `y` → 0
3. **Total the count**: The three `r`s appear at positions 3, 8, and 9 in the 10-letter word.
**Final count: 3**
11.4s215 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…
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
Solar Pro 4
### What's Causing the Error
The error `TypeError: Cannot read properties of undefined (reading 'map')` means that the `users` prop being passed to your `UserList` component is `undefined`. Since you're calling `.map()` directly on it, JavaScript throws an error because `undefined` doesn't have a `map` method.
This typically happens when:
- The parent component hasn't passed the `users` prop
- The prop is still loading (e.g., from an API call)
- The prop is conditionally undefined
---
### How to Fix It
You have a few options to handle this safely:
#### ✅ Option 1: Add a Default Prop Value (Recommended)
Provide a fallback empty array so `.map()` always has something to work with:
```j…
24.7s539 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):…
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
Solar Pro 4
Here’s a breakdown of the issues in the original function, followed by a refactored version and a detailed explanation of the improvements.
### 🔍 Key Issues in the Original Code
| Area | Problem |
|------|---------|
| **Import organization** | `import` inside the function is evaluated on every call. Imports should live at the top of the module. |
| **Exception handling** | Bare `except:` catches `SystemExit`, `KeyboardInterrupt`, and other fatal errors. Always catch specific exceptions (`requests.RequestException`). |
| **Loose equality** | `== True` is redundant and can cause subtle bugs. Use `if item["active"]:` or `.get()`. |
| **HTTP status handling** | Calling `.json()` only on `200`…
17.5s1172 output tokens
Frequently asked questions
- Which is cheaper, GLM 5.1 or Solar Pro 4?
- Per 1M output tokens, GLM 5.1 is ¥786.28 and Solar Pro 4 is ¥21.11 on FastMetal (yen, before tax), so Solar Pro 4 is cheaper.
- How do the context windows of GLM 5.1 and Solar Pro 4 compare?
- GLM 5.1 takes 204,800 tokens; Solar Pro 4 takes 524,288.
- Which ranks higher, GLM 5.1 or Solar Pro 4?
- GLM 5.1 ranks higher on the public arena (GLM 5.1 #49, Solar Pro 4 #173). Ranks move as the leaderboard updates.
- Can I use GLM 5.1 and Solar Pro 4 with the same API key?
- Yes. On FastMetal's OpenAI-compatible endpoint, switch by passing "glm-5.1" or "solar-pro4" 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 GLM 5.1 and Solar Pro 4 from the browser chat and the API. No monthly fee.