gpt-oss-120b vs Muse Spark 1.2
Pricing, context window and real answers (August 2026)
gpt-oss-120b (OpenAI) and Muse Spark 1.2 (Meta), 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
 gpt-oss-120b |  Muse Spark 1.2 | |
|---|---|---|
| Provider | OpenAI | Meta |
| Input (per 1M tokens) | ¥16 | ¥219.9 |
| Output (per 1M tokens) | ¥79 | ¥747.65 |
| Typical cost (1,000 in + 500 out tokens × 1,000 calls) | ¥56 | ¥594 |
| Context window | 131,072 tokens | 1,048,576 tokens |
| Release date | 8/5/2025 | 8/5/2026 |
| Input modalities | text | text, image, video, file, audio |
| Arena · overall | #196 · ELO 1,352 | #4 · ELO 1,498 |
| Arena · Japanese | #133 · ELO 1,328 | Unranked |
| Arena · coding | #203 · ELO 1,391 | #7 · ELO 1,533 |
Prices are FastMetal's yen rates before tax. Arena ranks are as of the latest leaderboard scrape.
Which should you pick?
- On price, gpt-oss-120b: ¥79 per 1M output tokens, 89% less than Muse Spark 1.2.
- On the Overall arena board, Muse Spark 1.2 ranks higher (#4; gpt-oss-120b is #196).
- On the Coding arena board, Muse Spark 1.2 ranks higher (#7; gpt-oss-120b is #203).
- For long documents, Muse Spark 1.2: a 1,048,576-token context window against 131,072 for gpt-oss-120b.
- 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.
gpt-oss-120b
**Step‑by‑step count of the letter “r” in the word “strawberry”**
1. Write out the word with each letter in order, labeling its position:
| Position | Letter |
|----------|--------|
| 1 | s |
| 2 | t |
| 3 | **r** |
| 4 | a |
| 5 | w |
| 6 | b |
| 7 | e |
| 8 | **r** |
| 9 | **r** |
|10 | y |
2. Scan the list and mark every occurrence of the letter **r**.
- Position 3 → r (first occurrence)
- Position 8 → r (second occurrence)
- Position 9 → r (third occurrence)
3. Count the marked entries: there are **3** marked positions.
**Result:** The word “strawberry” contains **3** occurrences of the letter **r**…
1.7s332 output tokens
Muse Spark 1.2
There are **3** 'r's in "strawberry".
Here is my reasoning step by step:
1. Write out the word and its spelling: **s-t-r-a-w-b-e-r-r-y**
2. Go through each letter one by one and check if it is an 'r':
* 1. s - not an 'r' -> count = 0
* 2. t - not an 'r' -> count = 0
* 3. **r** - yes, it's an 'r' -> count = 1
* 4. a - not an 'r' -> count = 1
* 5. w - not an 'r' -> count = 1
* 6. b - not an 'r' -> count = 1
* 7. e - not an 'r' -> count = 1
* 8. **r** - yes, it's an 'r' -> count = 2
* 9. **r** - yes, it's an 'r' -> count = 3
* 10. y - not an 'r' -> count = 3
3. Final total = **3**.
13.3s1123 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…
gpt-oss-120b
### Why the `map` can’t be called
`Array.prototype.map` is a method that exists only on **arrays** (or array‑like objects).
When you see
```
TypeError: Cannot read properties of undefined (reading 'map')
at UserList (...)
```
it means that the variable you think is an array – `users` in this case – is actually **`undefined`** (or `null`).
React is trying to evaluate this line:
```jsx
{users.map(user => <li key={user.id}>{user.name}</li>)}
```
and it crashes because you can’t read `.map` from `undefined`.
---
## Common reasons `users` ends up undefined
| Reason | Typical scenario | How it shows up |
|--------|------------------|-----------------|
| **Prop not passed** | `<Use…
7.3s1610 output tokens
Muse Spark 1.2
This error means `users` is `undefined` when the component tries to render.
You are calling `.map()` on `users` at line 12, but `.map()` only exists on arrays. If `users` is `undefined` or `null`, JavaScript throws: `Cannot read properties of undefined (reading 'map')`.
This usually happens for 2 reasons:
1. You didn't pass the `users` prop to the component: `<UserList />`
2. Your data is async and `users` is `undefined` on the first render. For example: `const [users, setUsers] = useState()` without an initial value, and the data hasn't been fetched yet.
### Fix it
You need to guarantee `users` is always an array before you call `.map()`.
#### 1. Best Fix: Give it a default value
U…
7.6s1142 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):…
gpt-oss-120b
Below is a **step‑by‑step review** of the original `get_data` implementation followed by a **refactored version** that addresses readability, performance, and modern Python best‑practice concerns.
---
## 1. What the original function does
```python
def get_data(url, retries=3):
import requests
import time
for i in range(retries):
try:
r = requests.get(url, timeout=10)
if r.status_code == 200:
data = r.json()
result = []
for item in data:
if item["active"] == True:
result.append({"name": item["name"], "id": item["id"]})
return result…
14.4s3132 output tokens
Muse Spark 1.2
Here is a review of your function with a refactored, production-ready version:
### Issues in the Current Version
#### 1. Readability
1. **Generic name:** `get_data` tells nothing about what it does. `get_active_items` is better.
2. **Imports inside function:** `import requests, time` should be at the top of the file. It's slower and violates PEP 8.
3. **Magic numbers:** `200`, `10`, `2` have no context.
4. **Verbose loop:** Manual `for` loop + `append` can be replaced with a list comprehension.
5. **No documentation/typing:** No docstring, no type hints, so callers don't know what it expects or returns.
6. **`== True` is redundant:** `if item["active"] == True:` should be `if item["a…
11.8s2278 output tokens
Frequently asked questions
- Which is cheaper, gpt-oss-120b or Muse Spark 1.2?
- Per 1M output tokens, gpt-oss-120b is ¥79 and Muse Spark 1.2 is ¥747.65 on FastMetal (yen, before tax), so gpt-oss-120b is cheaper.
- How do the context windows of gpt-oss-120b and Muse Spark 1.2 compare?
- gpt-oss-120b takes 131,072 tokens; Muse Spark 1.2 takes 1,048,576.
- Which ranks higher, gpt-oss-120b or Muse Spark 1.2?
- Muse Spark 1.2 ranks higher on the public arena (gpt-oss-120b #133, Muse Spark 1.2 #4). Ranks move as the leaderboard updates.
- Can I use gpt-oss-120b and Muse Spark 1.2 with the same API key?
- Yes. On FastMetal's OpenAI-compatible endpoint, switch by passing "gpt-oss-120b" or "muse-spark-1.2" 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 gpt-oss-120b and Muse Spark 1.2 from the browser chat and the API. No monthly fee.