Claude Opus 5 vs GLM 5.2
Pricing, context window and real answers (August 2026)
Claude Opus 5 (Anthropic) and GLM 5.2 (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 |  GLM 5.2 | |
|---|---|---|
| Provider | Anthropic | Z.ai |
| Input (per 1M tokens) | ¥893.5 | ¥250.18 |
| Output (per 1M tokens) | ¥4,467.5 | ¥786.28 |
| Typical cost (1,000 in + 500 out tokens × 1,000 calls) | ¥3,127 | ¥643 |
| Context window | 1,000,000 tokens | 1,048,576 tokens |
| Release date | 7/24/2026 | 6/16/2026 |
| Input modalities | text, image, file | text |
| Arena · overall | #5 · ELO 1,495 | #31 · ELO 1,469 |
| Arena · Japanese | Unranked | #13 · ELO 1,472 |
| Arena · coding | #7 · ELO 1,535 | #46 · ELO 1,506 |
Prices are FastMetal's yen rates before tax. Arena ranks are as of the latest leaderboard scrape.
Which should you pick?
- On price, GLM 5.2: ¥786.28 per 1M output tokens, 82% less than Claude Opus 5.
- On the Overall arena board, Claude Opus 5 ranks higher (#5; GLM 5.2 is #31).
- On the Coding arena board, Claude Opus 5 ranks higher (#7; GLM 5.2 is #46).
- For long documents, GLM 5.2: a 1,048,576-token context window against 1,000,000 for Claude Opus 5.
- 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
## Counting the 'r's in "strawberry"
**Step 1: Break the word into individual letters**
| Position | Letter |
|----------|--------|
| 1 | s |
| 2 | t |
| 3 | **r** |
| 4 | a |
| 5 | w |
| 6 | b |
| 7 | e |
| 8 | **r** |
| 9 | **r** |
| 10 | y |
**Step 2: Identify each occurrence of 'r'**
- Position 3: the 'r' in the "str-" beginning
- Position 8: the first 'r' in the "-rry" ending
- Position 9: the second 'r' in the "-rry" ending
**Step 3: Tally them up**
3 + 8 + 9 → that's **3 occurrences**.
## Answer: 3
The tricky part is that "strawberry" contains a *double* 'r' near the end ("berry"), which is easy to skim over as a single letter. Splitting the word into "straw" (1 'r') + "berry"…
7.1s466 output tokens
GLM 5.2
To count the number of 'r's in the word 'strawberry', let's look at the word letter by letter:
1. **s** - no 'r'
2. **t** - no 'r'
3. **r** - this is the 1st 'r'
4. **a** - no 'r'
5. **w** - no 'r'
6. **b** - no 'r'
7. **e** - no 'r'
8. **r** - this is the 2nd 'r'
9. **r** - this is the 3rd 'r'
10. **y** - no 'r'
Total count: 3
There are **3** 'r's in the word 'strawberry'.
2.6s439 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
## What's happening
The error means `users` is `undefined` when `UserList` renders — so calling `.map()` on it throws. React isn't the problem; the prop simply isn't there yet (or ever).
The three most common causes:
1. **The parent isn't passing the prop** (or passes it under a different name / typo):
```jsx
<UserList /> // users is undefined
<UserList user={data} /> // wrong name
```
2. **The data is fetched asynchronously**, and the first render happens before it arrives:
```jsx
const [users, setUsers] = useState(); // undefined on first render!
useEffect(() => { fetch('/api/users').then(r => r.json()).then(setUsers); }, []);
return <UserList user…
15.1s1191 output tokens
GLM 5.2
The error `TypeError: Cannot read properties of undefined (reading 'map')` happens because the `users` prop being passed to your `UserList` component is currently `undefined`. When JavaScript tries to call `.map()` on `undefined`, it throws this error.
Here are the best ways to fix this:
### Fix 1: Provide a default value (Recommended)
You can provide a default empty array `[]` when destructuring the props. This ensures that even if `users` is not passed down, the `.map()` function will still have an array to iterate over (resulting in an empty list rather than a crash).
```jsx
function UserList({ users = [] }) {
return (
<ul>
{users.map(user => <li key={user.id}>{user.name}</…
8.3s1006 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
# Code Review: `get_data`
Overall, the function works for the happy path, but there are several issues worth addressing — the most serious being the bare `except`, the silent failure mode, and the conflation of two responsibilities (fetching and transforming).
## Critical Issues
### 1. Bare `except` swallows everything
```python
except:
time.sleep(2)
```
This catches `KeyboardInterrupt`, `SystemExit`, `MemoryError`, and — importantly — bugs in your own code. If `item["active"]` raises a `KeyError` because the API changed its schema, you'll retry three times and return `[]`, giving you no indication anything went wrong. Catch `requests.RequestException` instead (the base class for all…
34.7s2823 output tokens
GLM 5.2
Here is a review of your Python function, broken down by readability, performance, and best practices, followed by a refactored version of the code.
### 1. Best Practices
* **Move imports to the top:** Importing modules inside a function is generally discouraged. While Python caches imports, putting `import requests` and `import time` at the top of your file is the standard convention and improves readability.
* **Avoid bare `except:` blocks:** Using a bare `except:` catches everything, including `KeyboardInterrupt` and `SystemExit`. This makes it hard to interrupt your program if it gets stuck in a loop. You should catch specific exceptions, such as `requests.exceptions.RequestException` (…
10.9s2061 output tokens
Frequently asked questions
- Which is cheaper, Claude Opus 5 or GLM 5.2?
- Per 1M output tokens, Claude Opus 5 is ¥4,467.5 and GLM 5.2 is ¥786.28 on FastMetal (yen, before tax), so GLM 5.2 is cheaper.
- How do the context windows of Claude Opus 5 and GLM 5.2 compare?
- Claude Opus 5 takes 1,000,000 tokens; GLM 5.2 takes 1,048,576.
- Which ranks higher, Claude Opus 5 or GLM 5.2?
- Claude Opus 5 ranks higher on the public arena (Claude Opus 5 #5, GLM 5.2 #13). Ranks move as the leaderboard updates.
- Can I use Claude Opus 5 and GLM 5.2 with the same API key?
- Yes. On FastMetal's OpenAI-compatible endpoint, switch by passing "anthropic-claude-opus-5" or "glm-5.2" 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 and GLM 5.2 from the browser chat and the API. No monthly fee.