Gemini 3.5 Flash vs Solar Pro 4
Pricing, context window and real answers (August 2026)
Gemini 3.5 Flash (Google) and Solar Pro 4 (Upstage), 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
 Gemini 3.5 Flash | Solar Pro 4 | |
|---|---|---|
| Provider | Upstage | |
| Input (per 1M tokens) | ¥268.05 | ¥5.28 |
| Output (per 1M tokens) | ¥1,608.3 | ¥21.11 |
| Typical cost (1,000 in + 500 out tokens × 1,000 calls) | ¥1,072 | ¥16 |
| Context window | 1,048,576 tokens | 524,288 tokens |
| Release date | 5/19/2026 | 8/10/2026 |
| Input modalities | text, image, video, file, audio | text |
| Arena · overall | #21 · ELO 1,479 | #173 · ELO 1,376 |
| Arena · Japanese | #17 · ELO 1,479 | Unranked |
| Arena · coding | #51 · ELO 1,508 | #140 · ELO 1,448 |
Prices are FastMetal's yen rates before tax. Arena ranks are as of the latest leaderboard scrape.
Which should you pick?
- On price, Solar Pro 4: ¥21.11 per 1M output tokens, 99% less than Gemini 3.5 Flash.
- On the Overall arena board, Gemini 3.5 Flash ranks higher (#21; Solar Pro 4 is #173).
- On the Coding arena board, Gemini 3.5 Flash ranks higher (#51; Solar Pro 4 is #140).
- For long documents, Gemini 3.5 Flash: a 1,048,576-token context window against 524,288 for Solar Pro 4.
- 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.
Gemini 3.5 Flash
There are **3** 'r's in the word "strawberry".
Here is the step-by-step breakdown of how to count them:
1. **Break the word down into its individual letters:**
* 1st letter: **s**
* 2nd letter: **t**
* 3rd letter: **r** (First 'r')
* 4th letter: **a**
* 5th letter: **w**
* 6th letter: **b**
* 7th letter: **e**
* 8th letter: **r** (Second 'r')
* 9th letter: **r** (Third 'r')
* 10th letter: **y**
2. **Identify and count only the 'r's:**
* s - t - **r** (1) - a - w - b - e - **r** (2) - **r** (3) - y
By counting them as we go through the word, we find a total of **3** 'r's.
4.8s601 output tokens
Solar Pro 4
The word "strawberry" contains **3** 'r's. Here's the step-by-step breakdown:
1. **Spell out the word explicitly** to isolate each letter:
`s - t - r - a - w - b - e - r - r - y`
2. **Scan through the letters in order** and count every instance of the lowercase letter `r`:
- `s` → 0
- `t` → 0
- `r` → **1**
- `a` → 0
- `w` → 0
- `b` → 0
- `e` → 0
- `r` → **2**
- `r` → **3**
- `y` → 0
3. **Total the count**: The three `r`s appear at positions 3, 8, and 9 in the 10-letter word.
**Final count: 3**
11.4s215 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…
Gemini 3.5 Flash
### What is causing this error?
The error `TypeError: Cannot read properties of undefined (reading 'map')` means that your `UserList` component is trying to call `.map()` on the `users` variable, but **`users` is currently `undefined`**.
This usually happens for one of two reasons:
1. **The parent component forgot to pass the prop:** `<UserList />` was rendered without the `users` attribute.
2. **Asynchronous data fetching:** The parent component fetches the users from an API, but the API request hasn't finished yet when the component first renders, so `users` starts as `undefined`.
---
### How to fix it
Here are the three best ways to fix this, depending on how you want your UI to beh…
11.2s1524 output tokens
Solar Pro 4
### What's Causing the Error
The error `TypeError: Cannot read properties of undefined (reading 'map')` means that the `users` prop being passed to your `UserList` component is `undefined`. Since you're calling `.map()` directly on it, JavaScript throws an error because `undefined` doesn't have a `map` method.
This typically happens when:
- The parent component hasn't passed the `users` prop
- The prop is still loading (e.g., from an API call)
- The prop is conditionally undefined
---
### How to Fix It
You have a few options to handle this safely:
#### ✅ Option 1: Add a Default Prop Value (Recommended)
Provide a fallback empty array so `.map()` always has something to work with:
```j…
24.7s539 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):…
Gemini 3.5 Flash
Here is a review of your function, followed by two improved versions (one that keeps your structure but makes it Pythonic, and one production-ready version that uses industry best practices).
---
### Key Areas for Improvement
1. **Imports inside the function:** `import requests` and `import time` should be at the top of the file (PEP 8). Keeping them inside the function slows down execution if the function is called repeatedly.
2. **Bare `except:` clause:** Using `except:` without specifying an exception type is a major anti-pattern. It catches things you don't want to catch, like `KeyboardInterrupt` (Ctrl+C) or `SystemExit`. It should target `requests.RequestException`.
3. **Implicit `Tr…
19.7s2975 output tokens
Solar Pro 4
Here’s a breakdown of the issues in the original function, followed by a refactored version and a detailed explanation of the improvements.
### 🔍 Key Issues in the Original Code
| Area | Problem |
|------|---------|
| **Import organization** | `import` inside the function is evaluated on every call. Imports should live at the top of the module. |
| **Exception handling** | Bare `except:` catches `SystemExit`, `KeyboardInterrupt`, and other fatal errors. Always catch specific exceptions (`requests.RequestException`). |
| **Loose equality** | `== True` is redundant and can cause subtle bugs. Use `if item["active"]:` or `.get()`. |
| **HTTP status handling** | Calling `.json()` only on `200`…
17.5s1172 output tokens
Frequently asked questions
- Which is cheaper, Gemini 3.5 Flash or Solar Pro 4?
- Per 1M output tokens, Gemini 3.5 Flash is ¥1,608.3 and Solar Pro 4 is ¥21.11 on FastMetal (yen, before tax), so Solar Pro 4 is cheaper.
- How do the context windows of Gemini 3.5 Flash and Solar Pro 4 compare?
- Gemini 3.5 Flash takes 1,048,576 tokens; Solar Pro 4 takes 524,288.
- Which ranks higher, Gemini 3.5 Flash or Solar Pro 4?
- Gemini 3.5 Flash ranks higher on the public arena (Gemini 3.5 Flash #17, Solar Pro 4 #173). Ranks move as the leaderboard updates.
- Can I use Gemini 3.5 Flash and Solar Pro 4 with the same API key?
- Yes. On FastMetal's OpenAI-compatible endpoint, switch by passing "gemini-3.5-flash" or "solar-pro4" 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 Gemini 3.5 Flash and Solar Pro 4 from the browser chat and the API. No monthly fee.