Claude Sonnet 4.6 vs MiMo-V2.5-Pro
Pricing, context window and real answers (August 2026)
Claude Sonnet 4.6 (Anthropic) and MiMo-V2.5-Pro (Xiaomi), 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
 Claude Sonnet 4.6 | MiMo-V2.5-Pro | |
|---|---|---|
| Provider | Anthropic | Xiaomi |
| Input (per 1M tokens) | ¥554.4 | ¥77.73 |
| Output (per 1M tokens) | ¥2,772 | ¥155.47 |
| Typical cost (1,000 in + 500 out tokens × 1,000 calls) | ¥1,940 | ¥155 |
| Context window | 1,000,000 tokens | 1,050,000 tokens |
| Release date | 2/17/2026 | 4/22/2026 |
| Input modalities | text, image | text |
| Arena · overall | #32 · ELO 1,472 | #40 · ELO 1,468 |
| Arena · Japanese | #41 · ELO 1,438 | #61 · ELO 1,418 |
| Arena · coding | #14 · ELO 1,528 | #27 · ELO 1,520 |
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, 94% less than Claude Sonnet 4.6.
- On the Overall arena board, Claude Sonnet 4.6 ranks higher (#32; MiMo-V2.5-Pro is #40).
- On the Japanese arena board, Claude Sonnet 4.6 ranks higher (#41; MiMo-V2.5-Pro is #61).
- On the Coding arena board, Claude Sonnet 4.6 ranks higher (#14; MiMo-V2.5-Pro is #27).
- For long documents, MiMo-V2.5-Pro: a 1,050,000-token context window against 1,000,000 for Claude Sonnet 4.6.
- 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.
Claude Sonnet 4.6
## Counting the letter 'r' in 'strawberry'
Let me go through the word letter by letter:
| Position | Letter | Is it 'r'? |
|----------|--------|------------|
| 1 | s | No |
| 2 | t | No |
| 3 | r | ✅ Yes |
| 4 | a | No |
| 5 | w | No |
| 6 | b | No |
| 7 | e | No |
| 8 | r | ✅ Yes |
| 9 | r | ✅ Yes |
| 10 | y | No |
## Result
There are **3 r's** in 'strawberry'.
2.2s181 output tokens
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
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…
Claude Sonnet 4.6
## Problem Analysis
The error occurs because `users` is `undefined` when the component renders. You're calling `.map()` on `undefined`, which throws a `TypeError`.
**Common causes:**
- The prop isn't passed by the parent component
- Data is still loading asynchronously when the component first renders
- The parent passes `undefined` or a misspelled prop name
---
## Solutions
### Option 1: Default Parameter Value (Simplest Fix)
```javascript
function UserList({ users = [] }) {
return (
<ul>
{users.map(user => <li key={user.id}>{user.name}</li>)}
</ul>
);
}
```
This assigns an empty array if `users` is `undefined`, so `.map()` always has an array to work with.
---
###…
9.4s798 output tokens
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
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):…
Claude Sonnet 4.6
## Code Review and Improvements
### Issues Identified
1. **Imports inside function** – should be at module level
2. **Bare `except`** – catches everything including `KeyboardInterrupt`, `SystemExit`
3. **`== True` comparison** – not Pythonic
4. **No logging/error visibility** – silent failures make debugging hard
5. **Magic numbers** – hardcoded `2`, `10` with no explanation
6. **No distinction between retriable/non-retriable errors** – e.g., 404 should not be retried
7. **Inefficient list building** – list comprehension is cleaner
8. **No exponential backoff** – fixed sleep is naive for real-world retry logic
9. **Missing type hints and docstring**
---
### Improved Version
```python
im…
14.4s1099 output tokens
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
Frequently asked questions
- Which is cheaper, Claude Sonnet 4.6 or MiMo-V2.5-Pro?
- Per 1M output tokens, Claude Sonnet 4.6 is ¥2,772 and MiMo-V2.5-Pro is ¥155.47 on FastMetal (yen, before tax), so MiMo-V2.5-Pro is cheaper.
- How do the context windows of Claude Sonnet 4.6 and MiMo-V2.5-Pro compare?
- Claude Sonnet 4.6 takes 1,000,000 tokens; MiMo-V2.5-Pro takes 1,050,000.
- Which ranks higher, Claude Sonnet 4.6 or MiMo-V2.5-Pro?
- Claude Sonnet 4.6 ranks higher on the public arena (Claude Sonnet 4.6 #41, MiMo-V2.5-Pro #61). Ranks move as the leaderboard updates.
- Can I use Claude Sonnet 4.6 and MiMo-V2.5-Pro with the same API key?
- Yes. On FastMetal's OpenAI-compatible endpoint, switch by passing "anthropic-claude-sonnet-4-6" or "mimo-v2.5-pro" 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 Claude Sonnet 4.6 and MiMo-V2.5-Pro from the browser chat and the API. No monthly fee.