gpt-oss-120b vs MiMo-V2.6-Pro
Pricing, context window and real answers (September 2026)
gpt-oss-120b (OpenAI) and MiMo-V2.6-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
 gpt-oss-120b | MiMo-V2.6-Pro | |
|---|---|---|
| Provider | OpenAI | Xiaomi |
| Input (per 1M tokens) | ¥16 | ¥77.73 |
| Output (per 1M tokens) | ¥79 | ¥155.47 |
| Typical cost (1,000 in + 500 out tokens × 1,000 calls) | ¥56 | ¥155 |
| Context window | 131,072 tokens | 1,048,576 tokens |
| Release date | 8/5/2025 | 9/21/2026 |
| Input modalities | text | text, image, video, audio |
| Throughput (p50) | — | — |
| Arena · overall | #201 · ELO 1,352 | Unranked |
| Arena · Japanese | #136 · ELO 1,328 | Unranked |
| Arena · coding | #208 · ELO 1,391 | Unranked |
Prices are FastMetal's yen rates before tax. Arena ranks are as of the latest leaderboard scrape.
Which should you pick?
- On price, gpt-oss-120b: ¥79 per 1M output tokens, 49% less than MiMo-V2.6-Pro.
- For long documents, MiMo-V2.6-Pro: a 1,048,576-token context window against 131,072 for gpt-oss-120b.
- 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.
gpt-oss-120b
**Step‑by‑step count of the letter “r” in the word “strawberry”**
1. Write out the word with each letter in order, labeling its position:
| Position | Letter |
|----------|--------|
| 1 | s |
| 2 | t |
| 3 | **r** |
| 4 | a |
| 5 | w |
| 6 | b |
| 7 | e |
| 8 | **r** |
| 9 | **r** |
|10 | y |
2. Scan the list and mark every occurrence of the letter **r**.
- Position 3 → r (first occurrence)
- Position 8 → r (second occurrence)
- Position 9 → r (third occurrence)
3. Count the marked entries: there are **3** marked positions.
**Result:** The word “strawberry” contains **3** occurrences of the letter **r**…
1.7s332 output tokens
MiMo-V2.6-Pro
# Counting the 'r's in "strawberry"
## Step 1: Spell out the word letter by letter
| Position | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
|----------|---|---|---|---|---|---|---|---|---|----|
| Letter | s | t | r | a | w | b | e | r | r | y |
## Step 2: Identify every 'r'
- **Position 3** → **r** ✅ (1st 'r')
- **Position 8** → **r** ✅ (2nd 'r')
- **Position 9** → **r** ✅ (3rd 'r')
All other letters (s, t, a, w, b, e, y) are not 'r'.
## Answer
There are **3** 'r's in "strawberry."
22.0s327 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…
gpt-oss-120b
### Why the `map` can’t be called
`Array.prototype.map` is a method that exists only on **arrays** (or array‑like objects).
When you see
```
TypeError: Cannot read properties of undefined (reading 'map')
at UserList (...)
```
it means that the variable you think is an array – `users` in this case – is actually **`undefined`** (or `null`).
React is trying to evaluate this line:
```jsx
{users.map(user => <li key={user.id}>{user.name}</li>)}
```
and it crashes because you can’t read `.map` from `undefined`.
---
## Common reasons `users` ends up undefined
| Reason | Typical scenario | How it shows up |
|--------|------------------|-----------------|
| **Prop not passed** | `<Use…
7.3s1610 output tokens
MiMo-V2.6-Pro
# Fixing `Cannot read properties of undefined (reading 'map')`
## The Problem
The `users` prop is `undefined` when the component renders. This happens because `.map()` is being called on something that doesn't exist — JavaScript can't iterate over `undefined`.
This typically occurs when:
- The parent component doesn't pass the `users` prop at all
- The data is still loading (e.g., from an API call)
- A destructuring default doesn't exist
## The Fix
### Option 1: Provide a default value (simplest)
```jsx
function UserList({ users = [] }) {
return (
<ul>
{users.map(user => <li key={user.id}>{user.name}</li>)}
</ul>
);
}
```
### Option 2: Add a safety check with conditi…
32.9s575 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):…
gpt-oss-120b
Below is a **step‑by‑step review** of the original `get_data` implementation followed by a **refactored version** that addresses readability, performance, and modern Python best‑practice concerns.
---
## 1. What the original function does
```python
def get_data(url, retries=3):
import requests
import time
for i in range(retries):
try:
r = requests.get(url, timeout=10)
if r.status_code == 200:
data = r.json()
result = []
for item in data:
if item["active"] == True:
result.append({"name": item["name"], "id": item["id"]})
return result…
14.4s3132 output tokens
MiMo-V2.6-Pro
# Code Review: `get_data` Function
## Issues Identified
Here's my review organized by category, with a final improved version at the end.
---
### 🔴 Best Practices
1. **Imports inside the function** — `import requests` and `import time` are executed on *every* call. Move them to the top of the file (module-level).
2. **Bare `except:`** — This catches *everything*, including `KeyboardInterrupt` and `SystemExit`. Always catch specific exceptions.
3. **`== True` comparison** — Verbose and unnecessary. Use the object's truthiness directly.
4. **No logging** — Silent failures make debugging nearly impossible.
5. **Magic numbers** — `timeout=10` and `time.sleep(2)` are unexplained constan…
42.5s983 output tokens
Frequently asked questions
- Which is cheaper, gpt-oss-120b or MiMo-V2.6-Pro?
- Per 1M output tokens, gpt-oss-120b is ¥79 and MiMo-V2.6-Pro is ¥155.47 on FastMetal (yen, before tax), so gpt-oss-120b is cheaper.
- How do the context windows of gpt-oss-120b and MiMo-V2.6-Pro compare?
- gpt-oss-120b takes 131,072 tokens; MiMo-V2.6-Pro takes 1,048,576.
- Can I use gpt-oss-120b and MiMo-V2.6-Pro with the same API key?
- Yes. On FastMetal's OpenAI-compatible endpoint, switch by passing "gpt-oss-120b" or "mimo-v2.6-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 gpt-oss-120b and MiMo-V2.6-Pro from the browser chat and the API. No monthly fee.