GPT-5 Mini vs Qwen3.8 Max
Pricing, context window and real answers (September 2026)
GPT-5 Mini (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-5 Mini |  Qwen3.8 Max | |
|---|---|---|
| Provider | OpenAI | Qwen |
| Input (per 1M tokens) | ¥44.68 | ¥357.4 |
| Output (per 1M tokens) | ¥357.4 | ¥1,072.2 |
| Typical cost (1,000 in + 500 out tokens × 1,000 calls) | ¥223 | ¥894 |
| Context window | 400,000 tokens | 1,000,000 tokens |
| Release date | 8/7/2025 | 8/3/2026 |
| Input modalities | text, image, file | text, image |
| Throughput (p50) | — | — |
| Arena · overall | #163 · ELO 1,390 | #22 · ELO 1,481 |
| Arena · Japanese | #109 · ELO 1,365 | #18 · ELO 1,469 |
| Arena · coding | #172 · ELO 1,431 | #24 · ELO 1,522 |
Prices are FastMetal's yen rates before tax. Arena ranks are as of the latest leaderboard scrape.
Which should you pick?
- On price, GPT-5 Mini: ¥357.4 per 1M output tokens, 67% less than Qwen3.8 Max.
- On the Overall arena board, Qwen3.8 Max ranks higher (#22; GPT-5 Mini is #163).
- On the Japanese arena board, Qwen3.8 Max ranks higher (#18; GPT-5 Mini is #109).
- On the Coding arena board, Qwen3.8 Max ranks higher (#24; GPT-5 Mini is #172).
- For long documents, Qwen3.8 Max: a 1,000,000-token context window against 400,000 for GPT-5 Mini.
- 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-5 Mini
We examine the word "strawberry" letter by letter:
1. s — not an r (count = 0)
2. t — not an r (count = 0)
3. r — 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 — an r (count = 2)
9. r — an r (count = 3)
10. y — not an r (count = 3)
Total number of 'r's = 3.
5.2s382 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-5 Mini
That error means users is undefined when you call users.map(...). map is an Array method, so calling it on undefined throws "Cannot read properties of undefined (reading 'map')".
Common causes
- The parent component didn't pass a users prop.
- users is still loading (e.g. fetched asynchronously) and is null/undefined until the fetch completes.
- The parent initialized users to null instead of an empty array.
How to fix
Choose one or more of these approaches depending on your app:
1) Initialize the parent state as an array
If users is state in the parent, initialize it to [] so the child always receives an array:
const [users, setUsers] = useState([]);
// fetch and setUsers(data)
2) Give…
8.0s966 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-5 Mini
Subject: Revised Delivery Date — two-week shift due to integration issues
Hi [Client Name],
I’m writing to let you know that we’ve uncovered unexpected technical challenges during integration testing that will delay the project delivery by two weeks. I apologize for the disruption and understand the impact this has on your plans. We are treating this with top priority and are confident we will deliver a stable, fully tested solution within the revised timeframe.
What happened
- During integration testing we discovered [a data synchronization/race condition/API compatibility/third‑party behavior] issue that affects core functionality and cannot be safely released without remediation and ve…
9.3s1305 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-5 Mini or Qwen3.8 Max?
- Per 1M output tokens, GPT-5 Mini is ¥357.4 and Qwen3.8 Max is ¥1,072.2 on FastMetal (yen, before tax), so GPT-5 Mini is cheaper.
- How do the context windows of GPT-5 Mini and Qwen3.8 Max compare?
- GPT-5 Mini takes 400,000 tokens; Qwen3.8 Max takes 1,000,000.
- Which ranks higher, GPT-5 Mini or Qwen3.8 Max?
- Qwen3.8 Max ranks higher on the public arena (GPT-5 Mini #109, Qwen3.8 Max #18). Ranks move as the leaderboard updates.
- Can I use GPT-5 Mini and Qwen3.8 Max with the same API key?
- Yes. On FastMetal's OpenAI-compatible endpoint, switch by passing "gpt-5-mini" 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-5 Mini and Qwen3.8 Max from the browser chat and the API. No monthly fee.