MiMo-V2.5-Pro vs Muse Spark 1.2
Pricing, context window and real answers (August 2026)
MiMo-V2.5-Pro (Xiaomi) and Muse Spark 1.2 (Meta), 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
| MiMo-V2.5-Pro |  Muse Spark 1.2 | |
|---|---|---|
| Provider | Xiaomi | Meta |
| Input (per 1M tokens) | ¥77.73 | ¥219.9 |
| Output (per 1M tokens) | ¥155.47 | ¥747.65 |
| Typical cost (1,000 in + 500 out tokens × 1,000 calls) | ¥155 | ¥594 |
| Context window | 1,050,000 tokens | 1,048,576 tokens |
| Release date | 4/22/2026 | 8/5/2026 |
| Input modalities | text | text, image, video, file, audio |
| Arena · overall | #40 · ELO 1,468 | #4 · ELO 1,498 |
| Arena · Japanese | #61 · ELO 1,418 | Unranked |
| Arena · coding | #27 · ELO 1,520 | #7 · ELO 1,533 |
Prices are FastMetal's yen rates before tax. Arena ranks are as of the latest leaderboard scrape.
Which should you pick?
- On price, MiMo-V2.5-Pro: ¥155.47 per 1M output tokens, 79% less than Muse Spark 1.2.
- On the Overall arena board, Muse Spark 1.2 ranks higher (#4; MiMo-V2.5-Pro is #40).
- On the Coding arena board, Muse Spark 1.2 ranks higher (#7; MiMo-V2.5-Pro is #27).
- For long documents, MiMo-V2.5-Pro: a 1,050,000-token context window against 1,048,576 for Muse Spark 1.2.
- 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.
MiMo-V2.5-Pro
## Counting the r's in "strawberry"
Let me go through each letter one by one:
| Position | Letter | Is it 'r'? |
|----------|--------|------------|
| 1 | s | No |
| 2 | t | No |
| 3 | **r** | ✅ Yes (#1) |
| 4 | a | No |
| 5 | w | No |
| 6 | b | No |
| 7 | e | No |
| 8 | **r** | ✅ Yes (#2) |
| 9 | **r** | ✅ Yes (#3) |
| 10 | y | No |
**There are 3 r's in "strawberry."**
The word breaks down as **straw·ber·ry**, and the r's appear at the end of "staw" and then twice in the double-r of "rry."
8.3s313 output tokens
Muse Spark 1.2
There are **3** 'r's in "strawberry".
Here is my reasoning step by step:
1. Write out the word and its spelling: **s-t-r-a-w-b-e-r-r-y**
2. Go through each letter one by one and check if it is an 'r':
* 1. s - not an 'r' -> count = 0
* 2. t - not an 'r' -> count = 0
* 3. **r** - yes, it's 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** - yes, it's an 'r' -> count = 2
* 9. **r** - yes, it's an 'r' -> count = 3
* 10. y - not an 'r' -> count = 3
3. Final total = **3**.
13.3s1123 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…
MiMo-V2.5-Pro
# Fixing `Cannot read properties of undefined (reading 'map')`
## The Problem
The error means `users` is `undefined` when the component first renders. This typically happens when:
1. **The parent component hasn't passed the `users` prop**
2. **The data is being fetched asynchronously and isn't available yet**
3. **The prop name is misspelled in the parent**
For example, the parent might be rendering it like this:
```jsx
// ❌ No users prop passed — `users` will be undefined
<UserList />
```
## Solutions
### 1. Add a Default Prop Value (Simple Fix)
```jsx
function UserList({ users = [] }) {
return (
<ul>
{users.map(user => <li key={user.id}>{user.name}</li>)}
</ul>
);
}…
14.4s680 output tokens
Muse Spark 1.2
This error means `users` is `undefined` when the component tries to render.
You are calling `.map()` on `users` at line 12, but `.map()` only exists on arrays. If `users` is `undefined` or `null`, JavaScript throws: `Cannot read properties of undefined (reading 'map')`.
This usually happens for 2 reasons:
1. You didn't pass the `users` prop to the component: `<UserList />`
2. Your data is async and `users` is `undefined` on the first render. For example: `const [users, setUsers] = useState()` without an initial value, and the data hasn't been fetched yet.
### Fix it
You need to guarantee `users` is always an array before you call `.map()`.
#### 1. Best Fix: Give it a default value
U…
7.6s1142 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):…
MiMo-V2.5-Pro
# Code Review: `get_data` Function
## Issues Identified
```
┌──────────────────────────────────────────────────────────────┐
│ ISSUE SEVERITY MAP │
├──────────────────┬────────────┬──────────────────────────────┤
│ Issue │ Severity │ Category │
├──────────────────┼────────────┼──────────────────────────────┤
│ Bare except │ 🔴 High │ Error Handling / Best Prac. │
│ Silent failures │ 🔴 High │ Debuggability │
│ == True check │ 🟡 Medium │ Readability / PEP 8 │
│ Inline imports │ 🟡 Medium │ Best Practice │
│ No type hints │ 🟡 Medium │ Best Practice…
10.4s1572 output tokens
Muse Spark 1.2
Here is a review of your function with a refactored, production-ready version:
### Issues in the Current Version
#### 1. Readability
1. **Generic name:** `get_data` tells nothing about what it does. `get_active_items` is better.
2. **Imports inside function:** `import requests, time` should be at the top of the file. It's slower and violates PEP 8.
3. **Magic numbers:** `200`, `10`, `2` have no context.
4. **Verbose loop:** Manual `for` loop + `append` can be replaced with a list comprehension.
5. **No documentation/typing:** No docstring, no type hints, so callers don't know what it expects or returns.
6. **`== True` is redundant:** `if item["active"] == True:` should be `if item["a…
11.8s2278 output tokens
Frequently asked questions
- Which is cheaper, MiMo-V2.5-Pro or Muse Spark 1.2?
- Per 1M output tokens, MiMo-V2.5-Pro is ¥155.47 and Muse Spark 1.2 is ¥747.65 on FastMetal (yen, before tax), so MiMo-V2.5-Pro is cheaper.
- How do the context windows of MiMo-V2.5-Pro and Muse Spark 1.2 compare?
- MiMo-V2.5-Pro takes 1,050,000 tokens; Muse Spark 1.2 takes 1,048,576.
- Which ranks higher, MiMo-V2.5-Pro or Muse Spark 1.2?
- Muse Spark 1.2 ranks higher on the public arena (MiMo-V2.5-Pro #61, Muse Spark 1.2 #4). Ranks move as the leaderboard updates.
- Can I use MiMo-V2.5-Pro and Muse Spark 1.2 with the same API key?
- Yes. On FastMetal's OpenAI-compatible endpoint, switch by passing "mimo-v2.5-pro" or "muse-spark-1.2" 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 MiMo-V2.5-Pro and Muse Spark 1.2 from the browser chat and the API. No monthly fee.