gpt-oss-120b vs Qwen3.8 Max
Pricing, context window and real answers (August 2026)
gpt-oss-120b (OpenAI) and Qwen3.8 Max (Qwen), 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 |  Qwen3.8 Max | |
|---|---|---|
| Provider | OpenAI | Qwen |
| Input (per 1M tokens) | ¥16 | ¥357.4 |
| Output (per 1M tokens) | ¥79 | ¥1,072.2 |
| Typical cost (1,000 in + 500 out tokens × 1,000 calls) | ¥56 | ¥894 |
| Context window | 131,072 tokens | 1,000,000 tokens |
| Release date | 8/5/2025 | 8/3/2026 |
| Input modalities | text | text, image |
| Arena · overall | #186 · ELO 1,352 | Unranked |
| Arena · Japanese | #123 · ELO 1,320 | Unranked |
| Arena · coding | #190 · ELO 1,390 | Unranked |
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, 93% less than Qwen3.8 Max.
- For long documents, Qwen3.8 Max: a 1,000,000-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
Qwen3.8 Max
The word **strawberry** is spelled:
**s t r a w b e r r y**
Now count the letter **r**:
1. s
2. t
3. **r** ← first r
4. a
5. w
6. b
7. e
8. **r** ← second r
9. **r** ← third r
10. y
There are **3** letters **r** in **strawberry**.
3.5s156 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
Qwen3.8 Max
The error means `users` is `undefined` when `UserList` tries to render:
```js
{users.map(user => ...)}
```
JavaScript cannot call `.map()` on `undefined`, so React throws:
```text
Cannot read properties of undefined (reading 'map')
```
## Most likely cause
The parent component is rendering `UserList` without passing a valid `users` array, or it is passing `users` before the data has loaded.
For example:
```jsx
<UserList />
```
or:
```jsx
<UserList users={undefined} />
```
or:
```jsx
const [users, setUsers] = useState(); // undefined initially
```
Then later:
```jsx
<UserList users={users} />
```
On the first render, `users` is still `undefined`.
---
## Fix 1: Give `users` a d…
17.7s1020 output tokens
Professional Email
Write a professional email to a client explaining that the project delivery will be delayed by two weeks due to unexpected technical challenges discovered during integration testing. The tone should be apologetic but con…
gpt-oss-120b
**Subject:** Updated Delivery Timeline for [Project Name] – Revised Schedule & Mitigation Plan
Dear **[Client Name]**,
I hope you are well. I am writing to inform you of a change to the delivery schedule for **[Project Name]**. During the recent integration testing phase our team uncovered an unexpected technical challenge in the **[specific component/module, e.g., “payment‑gateway API integration”]** that requires additional development and validation work.
### Why the Delay
- **Root cause:** A compatibility issue between the new **[third‑party service]** and our existing data‑mapping layer, which was not evident in the unit‑testing environment.
- **Impact:** Resolving the issue…
3.5s771 output tokens
Qwen3.8 Max
Subject: Revised Project Delivery Timeline – Updated Schedule and Next Steps
Dear [Client Name],
I hope this message finds you well.
I am writing to provide an update on the current status of the project and to inform you that, during our recent integration testing phase, we encountered several unexpected technical challenges that will impact the original delivery timeline. After careful review with the technical team, we now anticipate the revised delivery date will be [insert date – two weeks from original delivery date].
Please accept my sincere apologies for this delay. We understand the importance of this project and the expectations tied to the original schedule. While this situati…
11.9s547 output tokens
Frequently asked questions
- Which is cheaper, gpt-oss-120b or Qwen3.8 Max?
- Per 1M output tokens, gpt-oss-120b is ¥79 and Qwen3.8 Max is ¥1,072.2 on FastMetal (yen, before tax), so gpt-oss-120b is cheaper.
- How do the context windows of gpt-oss-120b and Qwen3.8 Max compare?
- gpt-oss-120b takes 131,072 tokens; Qwen3.8 Max takes 1,000,000.
- Can I use gpt-oss-120b and Qwen3.8 Max with the same API key?
- Yes. On FastMetal's OpenAI-compatible endpoint, switch by passing "gpt-oss-120b" or "qwen3.8-max" 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 Qwen3.8 Max from the browser chat and the API. No monthly fee.