Model comparison

GPT-4o-mini vs Inkling

Pricing, context window and real answers (September 2026)

GPT-4o-mini (OpenAI) and Inkling (Thinking Machines), 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

openai logoGPT-4o-miniInkling
ProviderOpenAIThinking Machines
Input (per 1M tokens)¥26.81¥178.7
Output (per 1M tokens)¥107.22¥723.74
Typical cost (1,000 in + 500 out tokens × 1,000 calls)¥80¥541
Context window128,000 tokens524,288 tokens
Release date7/18/20247/17/2026
Input modalitiestext, image, filetext, image, audio
Throughput (p50)
Arena · overall#251 · ELO 1,318#85 · ELO 1,440
Arena · Japanese#187 · ELO 1,250#63 · ELO 1,415
Arena · coding#259 · ELO 1,348#78 · ELO 1,492

Prices are FastMetal's yen rates before tax. Arena ranks are as of the latest leaderboard scrape.

Which should you pick?

  • On price, GPT-4o-mini: ¥107.22 per 1M output tokens, 85% less than Inkling.
  • On the Overall arena board, Inkling ranks higher (#85; GPT-4o-mini is #251).
  • On the Japanese arena board, Inkling ranks higher (#63; GPT-4o-mini is #187).
  • On the Coding arena board, Inkling ranks higher (#78; GPT-4o-mini is #259).
  • For long documents, Inkling: a 524,288-token context window against 128,000 for GPT-4o-mini.
  • 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-4o-mini

To count the number of 'r's in the word "strawberry," we can follow these steps: 1. **Identify the word**: We have the word "strawberry." 2. **Break down the letters**: Let's write out the letters in the word: - s - t - r - a - w - b - e - r - r - y 3. **Locate the 'r's**: Now, we need to look for the letter 'r' among these letters. - In the list of letters, we can see: - The first 'r' is in the 3rd position. - The second 'r' is in the 8th position. - The third 'r' is in the 9th position. 4. **Count the occurrences**: We check each position we identified: - There are three occurrences of 'r' in the word "strawberry." 5. **Conclusion**:…
2.1s239 output tokens

Inkling

Let's break down the word **"strawberry"** letter by letter: 1. **s** 2. **t** 3. **r** ← (1st 'r') 4. **a** 5. **w** 6. **b** 7. **e** 8. **r** ← (2nd 'r') 9. **r** ← (3rd 'r') 10. **y** So the spelling is: s-t-**r**-a-w-b-e-**r**-**r**-y Counting them up: - One 'r' in "str" (the 3rd letter) - Two 'r's in "berry" (the 8th and 9th letters) **Total: 3 'r's** in "strawberry".**
2.4s417 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-4o-mini

The error you're encountering, `TypeError: Cannot read properties of undefined (reading 'map')`, indicates that the `users` prop is `undefined` when you try to call the `map` method on it. In your `UserList` component, you're attempting to use `users.map(...)`, but if the `users` prop is not provided or is `undefined`, this will throw an error. ### Fixing the Error 1. **Default Props**: You can set a default value for the `users` prop to prevent the error when it is `undefined`. ```jsx function UserList({ users = [] }) { // Default to an empty array return ( <ul> {users.map(user => <li key={user.id}>{user.name}</li>)} </ul> ); } ```…
5.0s511 output tokens

Inkling

The error occurs because `users` is `undefined` when `UserList` renders, so `users.map` fails. This usually happens when: - The parent doesn't pass the prop (`<UserList />` instead of `<UserList users={...} />`) - Data is still loading (e.g., API hasn't returned yet) ## Quick Fix Provide a default empty array so `.map` always has an array to work with: ```jsx function UserList({ users = [] }) { return ( <ul> {users.map(user => <li key={user.id}>{user.name}</li>)} </ul> ); } ``` Alternatively, guard against undefined explicitly: ```jsx function UserList({ users }) { if (!users) return null; // or a loading state return ( <ul> {users.map(user => <li key={…
4.9s585 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-4o-mini

Your Python function, `get_data`, essentially performs a GET request, handles retries on failure, and processes the response JSON to return a filtered list of dictionaries. Below, I've highlighted several improvements regarding readability, performance, and best practices: 1. **Avoid blanket exceptions**: It’s best practice to specify which exceptions you expect, allowing for better debugging and error handling. 2. **Use `requests` built-in exception handling**: Handle specific requests exceptions, such as `requests.exceptions.RequestException`. 3. **Improve condition checks**: Check for `item['active']` directly instead of comparing to `True`, which is more Pythonic. 4. **Use `time.sl…
8.8s628 output tokens

Inkling

Here is a review with an improved version followed by explanations. ### Issues in the original - **Imports inside the function**: Re-importing on every call is inefficient. - **Bare `except:`**: Catches `SystemExit`, `KeyboardInterrupt`, etc. - **Silent failures**: No logging; errors disappear. - **Magic numbers**: `10`, `2`, `200` are hard-coded. - **Data validation missing**: Assumes `data` is a list and every item has `"active"`, `"name"`, and `"id"` (will crash with `KeyError`). - **Performance**: Uses `.append()` in a loop instead of a list comprehension. - **Ambiguous return**: `[]` means both "success with no results" and "total failure". ### Improved version ```python import loggi…
54.1s5649 output tokens

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Frequently asked questions

Which is cheaper, GPT-4o-mini or Inkling?
Per 1M output tokens, GPT-4o-mini is ¥107.22 and Inkling is ¥723.74 on FastMetal (yen, before tax), so GPT-4o-mini is cheaper.
How do the context windows of GPT-4o-mini and Inkling compare?
GPT-4o-mini takes 128,000 tokens; Inkling takes 524,288.
Which ranks higher, GPT-4o-mini or Inkling?
Inkling ranks higher on the public arena (GPT-4o-mini #187, Inkling #63). Ranks move as the leaderboard updates.
Can I use GPT-4o-mini and Inkling with the same API key?
Yes. On FastMetal's OpenAI-compatible endpoint, switch by passing "gpt-4o-mini" or "inkling" 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-4o-mini and Inkling from the browser chat and the API. No monthly fee.

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