Kimi K3.1 Pro vs Qwen3.8 27B
Pricing, context window and real answers (October 2026)
Kimi K3.1 Pro (Moonshot) and Qwen3.8 27B (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
 Kimi K3.1 Pro |  Qwen3.8 27B | |
|---|---|---|
| Provider | Moonshot | Qwen |
| Input (per 1M tokens) | $2.11 | $0.211 |
| Output (per 1M tokens) | $10.55 | $2.64 |
| Typical cost (1,000 in + 500 out tokens × 1,000 calls) | $7.39 | $1.53 |
| Context window | 1,048,576 tokens | 1,000,000 tokens |
| Release date | 10/23/2026 | 8/14/2026 |
| Input modalities | text, image, video | text, image, video |
| Throughput (p50) | — | 45 tokens/s (n=26) |
| Arena · overall | Unranked | #102 · ELO 1,437 |
| Arena · Japanese | Unranked | #92 · ELO 1,397 |
| Arena · coding | Unranked | #82 · ELO 1,499 |
Prices are FastMetal's rates, before tax.
Rankings: LMArena leaderboard dataset (lmarena-ai/leaderboard-dataset), CC BY 4.0, snapshot 2026-10-22; category names mapped and ratings rounded by FastMetal.
Which should you pick?
- On price, Qwen3.8 27B: $2.64 per 1M output tokens, 75% less than Kimi K3.1 Pro.
- For long documents, Kimi K3.1 Pro: a 1,048,576-token context window against 1,000,000 for Qwen3.8 27B.
- 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.
Kimi K3.1 Pro
There are **3** ‘r’s in **“strawberry.”**
1. Write out each letter: **s – t – r – a – w – b – e – r – r – y**
2. Locate the ‘r’s: positions **3, 8, and 9**.
3. Count them: **1 + 1 + 1 = 3**.
11.3s
Qwen3.8 27B
The word is: **strawberry**
Break it into letters:
1. s
2. t
3. r
4. a
5. w
6. b
7. e
8. r
9. r
10. y
Now count the **r**’s:
- 3rd letter: **r**
- 8th letter: **r**
- 9th letter: **r**
So, there are **3** r’s in **strawberry**.
3.6s239 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…
Kimi K3.1 Pro
## What's causing the error
The error means `users` is `undefined` when the component renders, and you can't call `.map()` on `undefined`. The component itself is fine — the problem is that whatever renders `<UserList />` either isn't passing the prop, or is passing a value that isn't an array yet.
The most common cause is **async data fetching**: the parent renders `UserList` before the data has loaded.
```jsx
function App() {
const [users, setUsers] = useState(); // ❌ undefined on first render
useEffect(() => {
fetch('/api/users')
.then(res => res.json())
.then(setUsers);
}, []);
return <UserList users={users} />; // users is undefined here initially
}
```
On…
36.3s
Qwen3.8 27B
The error means that `users` is `undefined` when `UserList` renders:
```jsx
{users.map(...)}
```
JavaScript cannot call `.map()` on `undefined`.
For example, this would cause the error:
```jsx
<UserList />
```
because `users` is not being passed in.
## Simple fix: give `users` a default value
```jsx
function UserList({ users = [] }) {
return (
<ul>
{users.map(user => <li key={user.id}>{user.name}</li>)}
</ul>
);
}
```
Now if `users` is not passed in, it defaults to an empty array.
## Better fix: make sure the parent passes an array
Wherever you use `UserList`, pass `users`:
```jsx
<UserList users={users} />
```
If `users` comes from an API or state, make sure it…
9.5s601 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):…
Kimi K3.1 Pro
The timeout and bounded retry loop are good starting points. The biggest issue is that failures—and even programming errors—are silently converted into retries and then `[]`.
### Suggested improvements
- **Avoid bare `except:`**. It catches `KeyboardInterrupt`, `KeyError`, JSON/schema errors, and other bugs. Retry only expected transient network failures; let malformed responses fail visibly.
- **Use a deliberate retry policy**. Retrying `401`, `403`, or `404` usually wastes time. Retry only transient statuses, use exponential backoff, and avoid sleeping after the final attempt.
- **Do not use `[]` for both failure and no results**. Prefer raising the final exception so callers can disting…
560.2s
Qwen3.8 27B
The function works at a basic level, but it has several readability, reliability, and best-practice issues.
## Main issues
1. **Imports inside the function**
```python
import requests
import time
```
Imports should normally be at the top of the module unless there is a specific reason to lazy-load them.
2. **Bare `except` is too broad**
```python
except:
time.sleep(2)
```
This catches almost everything, including `KeyboardInterrupt`, `SystemExit`, `KeyError`, `TypeError`, and other programming errors. It makes debugging harder and can retry failures that should not be retried.
3. **It retries on every non-`200` status**
Retrying `401 Unauthorized`, `4…
205.9s13103 output tokens
Frequently asked questions
- Which is cheaper, Kimi K3.1 Pro or Qwen3.8 27B?
- Per 1M output tokens, Kimi K3.1 Pro is $10.55 and Qwen3.8 27B is $2.64 on FastMetal (US dollars, before tax), so Qwen3.8 27B is cheaper.
- How do the context windows of Kimi K3.1 Pro and Qwen3.8 27B compare?
- Kimi K3.1 Pro takes 1,048,576 tokens; Qwen3.8 27B takes 1,000,000.
- Can I use Kimi K3.1 Pro and Qwen3.8 27B with the same API key?
- Yes. On FastMetal's OpenAI-compatible endpoint, switch by passing "kimi-k3.1-pro" or "qwen3.8-27b" 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 Kimi K3.1 Pro and Qwen3.8 27B from the browser chat and the API. No monthly fee.