Model comparison

Kimi K3 vs Qwen3.8 27B

Pricing, context window and real answers (August 2026)

Kimi K3 (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

moonshotai logoKimi K3qwen logoQwen3.8 27B
ProviderMoonshotQwen
Input (per 1M tokens)¥536.1¥80.41
Output (per 1M tokens)¥2,680.5¥571.84
Typical cost (1,000 in + 500 out tokens × 1,000 calls)¥1,876¥366
Context window1,048,576 tokens1,000,000 tokens
Release date7/16/20268/14/2026
Input modalitiestext, imagetext, image, video
Arena · overall#10 · ELO 1,489#87 · ELO 1,436
Arena · Japanese#4 · ELO 1,510Unranked
Arena · coding#6 · ELO 1,543#67 · ELO 1,498

Prices are FastMetal's yen rates before tax. Arena ranks are as of the latest leaderboard scrape.

Which should you pick?

  • On price, Qwen3.8 27B: ¥571.84 per 1M output tokens, 79% less than Kimi K3.
  • On the Overall arena board, Kimi K3 ranks higher (#10; Qwen3.8 27B is #87).
  • On the Coding arena board, Kimi K3 ranks higher (#6; Qwen3.8 27B is #67).
  • For long documents, Kimi K3: 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

# Counting the 'r's in "strawberry" **Step 1: Write out each letter with its position** | 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 'r'** - Position 3: the 'r' in "st**r**" - Position 8: the first 'r' in "be**r**ry" - Position 9: the second 'r' in "ber**r**y" **Step 3: Verify by splitting the word** "Strawberry" = "straw" + "berry" - "straw" contains **1** r - "berry" contains **2** r's **Answer: There are 3 r's in "strawberry."** 🍓
12.2s594 output tokens

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

## What's causing it The error means `users` is `undefined` when the component renders — `.map()` only exists on arrays, so calling it on `undefined` throws. Your component code is fine; the problem is **upstream**: whatever renders `<UserList />` isn't passing a valid array. The most common culprit is **async data fetching with uninitialized state** in the parent: ```jsx function App() { const [users, setUsers] = useState(); // ← undefined! useEffect(() => { fetch('/api/users') .then(res => res.json()) .then(setUsers); }, []); return <UserList users={users} />; // undefined on first render } ``` The component renders *before* the fetch resolves, so `users` is `…
47.5s1756 output tokens

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

This works, but there are several issues worth addressing. Here's a breakdown, followed by an improved version. ## Issues ### Correctness & best practices 1. **Bare `except:`** — catches *everything*, including `KeyboardInterrupt` and programming bugs like `KeyError` on a malformed item (which then get pointlessly retried). Catch `requests.RequestException` specifically. 2. **Silent failures** — errors are swallowed with no logging, and returning `[]` makes "API is down" indistinguishable from "no active items." At minimum, log; ideally, raise after the final attempt. 3. **Retrying non-retryable errors** — a 400/401/404 will never succeed on retry, but the code sleeps and retries anyway. O…
57.6s8060 output tokens

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

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Frequently asked questions

Which is cheaper, Kimi K3 or Qwen3.8 27B?
Per 1M output tokens, Kimi K3 is ¥2,680.5 and Qwen3.8 27B is ¥571.84 on FastMetal (yen, before tax), so Qwen3.8 27B is cheaper.
How do the context windows of Kimi K3 and Qwen3.8 27B compare?
Kimi K3 takes 1,048,576 tokens; Qwen3.8 27B takes 1,000,000.
Which ranks higher, Kimi K3 or Qwen3.8 27B?
Kimi K3 ranks higher on the public arena (Kimi K3 #4, Qwen3.8 27B #87). Ranks move as the leaderboard updates.
Can I use Kimi K3 and Qwen3.8 27B with the same API key?
Yes. On FastMetal's OpenAI-compatible endpoint, switch by passing "kimi-k3" 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 and Qwen3.8 27B from the browser chat and the API. No monthly fee.

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