Claude Opus 5.5 vs GLM 4.7
Pricing, context window and real answers (September 2026)
Claude Opus 5.5 (Anthropic) and GLM 4.7 (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
 Claude Opus 5.5 |  GLM 4.7 | |
|---|---|---|
| Provider | Anthropic | Z.ai |
| Input (per 1M tokens) | ¥692.4 | ¥107.22 |
| Output (per 1M tokens) | ¥3,462 | ¥393.14 |
| Typical cost (1,000 in + 500 out tokens × 1,000 calls) | ¥2,423 | ¥304 |
| Context window | 1,000,000 tokens | 202,752 tokens |
| Release date | 9/22/2026 | 12/22/2025 |
| Input modalities | text, image, file | text |
| Throughput (p50) | — | — |
| Arena · overall | Unranked | #83 · ELO 1,442 |
| Arena · Japanese | Unranked | Unranked |
| Arena · coding | Unranked | #91 · ELO 1,485 |
Prices are FastMetal's yen rates before tax. Arena ranks are as of the latest leaderboard scrape.
Which should you pick?
- On price, GLM 4.7: ¥393.14 per 1M output tokens, 89% less than Claude Opus 5.5.
- For long documents, Claude Opus 5.5: a 1,000,000-token context window against 202,752 for GLM 4.7.
- 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.
Claude Opus 5.5
# Counting 'r's in "strawberry"
**Step 1: Spell out the word letter by letter.**
| Position | Letter |
|----------|--------|
| 1 | s |
| 2 | t |
| 3 | **r** ← |
| 4 | a |
| 5 | w |
| 6 | b |
| 7 | e |
| 8 | **r** ← |
| 9 | **r** ← |
| 10 | y |
**Step 2: Mark each 'r'.**
- Position 3: the "r" in "st**r**aw"
- Positions 8 and 9: the double "rr" in "be**rr**y"
**Step 3: Add them up.**
1 (in "straw") + 2 (in "berry") = **3**
**Answer: There are 3 'r's in "strawberry."**
A common mistake is to count only 2, because the double "rr" in "berry" can be read as a single sound. Breaking the word into its parts, "straw" + "berry," makes all three easy to see.
5.4s376 output tokens
GLM 4.7
There are **3** "r"s in "strawberry".
Here is the step-by-step reasoning:
1. **Break down the word into individual letters:**
s - t - r - a - w - b - e - r - r - y
2. **Identify the position of each 'r':**
* The 3rd letter is **r**.
* The 8th letter is **r**.
* The 9th letter is **r**.
3. **Count the total occurrences:**
1 + 1 + 1 = 3.
23.3s685 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…
Claude Opus 5.5
## What's causing it
The error means `users` is `undefined` when `UserList` renders, so `users.map(...)` fails. The component itself is fine. The problem is the value it receives from its parent. Common reasons:
1. **Async data hasn't loaded yet.** This is the most common cause. The parent fetches users from an API, and on the first render the state is still `undefined`:
```jsx
const [users, setUsers] = useState(); // undefined on first render
useEffect(() => {
fetch('/api/users').then(r => r.json()).then(setUsers);
}, []);
return <UserList users={users} />; // crashes before fetch completes
```
2. **The prop isn't being passed**, or has a different name:
```js…
10.9s1040 output tokens
GLM 4.7
### The Cause
The error `TypeError: Cannot read properties of undefined (reading 'map')` means that the variable `users` is `undefined` when the component tries to render.
In React, this typically happens for one of two reasons:
1. The **Parent Component** is not passing the `users` prop to `UserList`.
2. The **Parent Component** passed the prop, but the data hasn't loaded yet (e.g., an API call is still pending), so the value is initially `undefined`.
Since `undefined` does not have a `.map()` method, the application crashes.
---
### How to Fix It
There are two main ways to fix this: handling it inside the `UserList` component (defensive coding) or fixing the parent component passing…
42.0s1384 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):…
Claude Opus 5.5
# Code Review: `get_data`
The function works in the happy path, but it has several issues that can hide bugs, waste time, and make failures hard to diagnose.
## Issues
### 🔴 Correctness and Reliability
**1. The bare `except:` is the most serious problem.**
It catches everything, including `KeyboardInterrupt`, `SystemExit`, and bugs in your own code. For example, if an item is missing the `"name"` key, the resulting `KeyError` gets swallowed and the request is retried as if it were a network error. The same happens with invalid JSON. Catch only the exceptions you expect, such as `requests.ConnectionError` and `requests.Timeout`.
**2. Failure is indistinguishable from "no results."**
Ret…
33.5s4023 output tokens
GLM 4.7
Here is a review of your function with suggestions for improving readability, performance, and best practices, followed by a refactored version of the code.
### Code Review
1. **Import Placement:** You import `requests` and `time` inside the function. Imports should generally be placed at the top of the file so they are loaded once when the module starts, rather than every time the function is called.
2. **Bare `except:`:** You used `except:` without specifying an exception type. This is dangerous because it catches *everything*, including `KeyboardInterrupt` (Ctrl+C) and `SystemExit`, preventing your program from terminating when needed. You should specifically catch `requests.exception…
24.5s2951 output tokens
Frequently asked questions
- Which is cheaper, Claude Opus 5.5 or GLM 4.7?
- Per 1M output tokens, Claude Opus 5.5 is ¥3,462 and GLM 4.7 is ¥393.14 on FastMetal (yen, before tax), so GLM 4.7 is cheaper.
- How do the context windows of Claude Opus 5.5 and GLM 4.7 compare?
- Claude Opus 5.5 takes 1,000,000 tokens; GLM 4.7 takes 202,752.
- Can I use Claude Opus 5.5 and GLM 4.7 with the same API key?
- Yes. On FastMetal's OpenAI-compatible endpoint, switch by passing "anthropic-claude-opus-5-5" or "glm-4.7" 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 Claude Opus 5.5 and GLM 4.7 from the browser chat and the API. No monthly fee.