FastMetal

Model comparison

Kimi K3.1 Pro vs MiniMax M3.1 Flash

Pricing, context window and real answers (October 2026)

Kimi K3.1 Pro (Moonshot) and MiniMax M3.1 Flash (MiniMax), 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 K3.1 Prominimax logoMiniMax M3.1 Flash
ProviderMoonshotMiniMax
Input (per 1M tokens)$2.11$0.1583
Output (per 1M tokens)$10.55$0.633
Typical cost (1,000 in + 500 out tokens × 1,000 calls)$7.39$0.4748
Context window1,048,576 tokens1,048,576 tokens
Release date10/23/202610/19/2026
Input modalitiestext, image, videotext, image
Throughput (p50)——
Arena · overallUnrankedUnranked
Arena · JapaneseUnrankedUnranked
Arena · codingUnrankedUnranked

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, MiniMax M3.1 Flash: $0.633 per 1M output tokens, 94% less than Kimi K3.1 Pro.
  • 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

MiniMax M3.1 Flash

1. Spell **strawberry**: **s – t – r – a – w – b – e – r – r – y** 2. Count the letter **r**: it appears at positions **3, 8, and 9**. **Total: 3 “r”s.**
3.0s193 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

MiniMax M3.1 Flash

The error occurs because `users` is `undefined` when `UserList` renders. Calling `.map()` on `undefined` causes the `TypeError`. This commonly happens when: - `<UserList />` is rendered without passing the `users` prop. - The prop has a different name, such as `user`. - Data is still loading and the parent initializes its state as `undefined`. - An API response is accessed before it exists. ### Immediate fix Provide a default empty array: ```jsx function UserList({ users = [] }) { return ( <ul> {users.map(user => ( <li key={user.id}>{user.name}</li> ))} </ul> ); } ``` Then pass the actual data from the parent: ```jsx const [users, setUsers] = useState([…
7.3s744 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

MiniMax M3.1 Flash

The function is understandable, but it has a few important issues: - `except:` catches programming errors such as `KeyError`, `TypeError`, and even `KeyboardInterrupt`. - Every non-200 response is retried, including permanent failures such as 400, 401, and 404. - It sleeps after the final failed attempt. - Returning `[]` makes a failed request indistinguishable from a successful response containing no active records. - A fixed delay can cause clients to retry simultaneously; exponential backoff and `Retry-After` are preferable. - `item["active"] == True` should be `item.get("active") is True` if the API contract says it is a JSON boolean. - A `Session` can reuse connections, while `requests…
146.5s

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Frequently asked questions

Which is cheaper, Kimi K3.1 Pro or MiniMax M3.1 Flash?
Per 1M output tokens, Kimi K3.1 Pro is $10.55 and MiniMax M3.1 Flash is $0.633 on FastMetal (US dollars, before tax), so MiniMax M3.1 Flash is cheaper.
How do the context windows of Kimi K3.1 Pro and MiniMax M3.1 Flash compare?
Kimi K3.1 Pro takes 1,048,576 tokens; MiniMax M3.1 Flash takes 1,048,576.
Can I use Kimi K3.1 Pro and MiniMax M3.1 Flash with the same API key?
Yes. On FastMetal's OpenAI-compatible endpoint, switch by passing "kimi-k3.1-pro" or "minimax-m3.1-flash" 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 MiniMax M3.1 Flash from the browser chat and the API. No monthly fee.

Create a free accountTry Kimi K3.1 Pro in chatTry MiniMax M3.1 Flash in chat

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