Model comparison

Claude Sonnet 5.5 vs Llama 3.1 8B Instruct

Pricing, context window and real answers (September 2026)

Claude Sonnet 5.5 (Anthropic) and Llama 3.1 8B Instruct (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

anthropic logoClaude Sonnet 5.5meta-llama logoLlama 3.1 8B Instruct
ProviderAnthropicMeta
Input (per 1M tokens)¥357.4¥3.36
Output (per 1M tokens)¥1,787¥6.72
Typical cost (1,000 in + 500 out tokens × 1,000 calls)¥1,251¥7
Context window1,000,000 tokens131,072 tokens
Release date9/28/20267/23/2024
Input modalitiestext, image, filetext
Throughput (p50)——
Arena · overallUnranked#336 · ELO 1,211
Arena · JapaneseUnranked#249 · ELO 1,087
Arena · codingUnranked#330 · ELO 1,260

Prices are FastMetal's yen rates before tax.

Rankings: LMArena leaderboard dataset (lmarena-ai/leaderboard-dataset), CC BY 4.0, snapshot 2026-09-25; category names mapped and ratings rounded by FastMetal.

Which should you pick?

  • On price, Llama 3.1 8B Instruct: ¥6.72 per 1M output tokens, 100% less than Claude Sonnet 5.5.
  • For long documents, Claude Sonnet 5.5: a 1,000,000-token context window against 131,072 for Llama 3.1 8B Instruct.
  • 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 5.5

Let me go through the word letter by letter. **strawberry** | Position | Letter | |---|---| | 1 | s | | 2 | t | | 3 | **r** ← 1st | | 4 | a | | 5 | w | | 6 | b | | 7 | e | | 8 | **r** ← 2nd | | 9 | **r** ← 3rd | | 10 | y | **Step-by-step reasoning:** 1. I split the word into individual letters: s-t-r-a-w-b-e-r-r-y (10 letters total). 2. I checked each letter for 'r'. 3. The first 'r' is in position 3, in "str…". 4. The second and third 'r's are in positions 8 and 9, in the "…rry" ending. **Answer: There are 3 r's in "strawberry".** A common mistake is to see "berry" as having only one 'r' (or to treat the double-r as a single letter), which leads to the incorrect answer of 2.
3.1s332 output tokens

Llama 3.1 8B Instruct

To count the number of 'r's in 'strawberry', I will break down the word into its individual letters and examine each one. Here's the step-by-step process: 1. The word 'strawberry' consists of the following letters: s-t-r-a-w-b-e-r-r-y. 2. I will start by counting the letters that are not 'r'. The word has 1 's', 1 't', 1 'a', 1 'w', 1 'b', 1 'e', 1 'y'. 3. Next, I will count the number of 'r's. The word has 2 'r's, one of which is part of the letter combination 'rr'. Therefore, there are 2 'r's in the word 'strawberry'.
9.7s169 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 5.5

## Cause `users` is `undefined` when the component renders, so `users.map(...)` throws. This happens when: 1. **The parent doesn't pass the prop**, or passes it under a different name (e.g. `<UserList data={x} />` or a typo like `user=`). 2. **The data loads asynchronously.** On the first render, the state or fetch result hasn't arrived yet. 3. **The value is wrong.** For example, the API returns `{ users: [...] }` and you passed the whole object, or you're reading a property that doesn't exist (`response.data.users` vs `response.users`). ## Fixes ### 1. Default value (simplest) ```jsx function UserList({ users = [] }) { return ( <ul> {users.map(user => <li key={user.id}>{use…
6.7s824 output tokens

Llama 3.1 8B Instruct

The error `TypeError: Cannot read properties of undefined (reading 'map')` typically occurs when you're trying to access a property (in this case, `map`) on an object that is `undefined`. In your case, the `users` prop passed to the `UserList` component is `undefined`. This is likely because the parent component that renders `UserList` is not passing the `users` prop, or the prop is not being properly initialized. To fix this error, you can add a simple check to ensure that `users` is not `undefined` before trying to call `map` on it: ```javascript function UserList({ users }) { if (!users) return null; // or return a default message, e.g. "No users found" return ( <ul> {us…
7.9s292 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 5.5

# Code Review ## Main Issues ### 1. Bare `except:` hides bugs (most important) It catches everything, including `KeyboardInterrupt` and `SystemExit`. It also wraps your parsing logic, so a missing `"active"` key (`KeyError`) or bad JSON is treated as a network failure, retried 3 times with sleeps, and then silently becomes `[]`. Catch only `requests.RequestException`, and keep parsing outside the `try`. ### 2. Silent failure Returning `[]` after all retries fails is indistinguishable from "the server returned no active items." Callers can't tell whether something went wrong. Raise an exception (or at least log) once retries are exhausted. ### 3. Retry logic - It sleeps after the final at…
20.9s3003 output tokens

Llama 3.1 8B Instruct

Here are some suggestions for improving the function's readability, performance, and best practices: **Readability Improvements** 1. **Function name**: Consider renaming `get_data` to `fetch_active_items` to better reflect its purpose. 2. **Variable naming**: Use more descriptive variable names, such as `response` instead of `r`, and `active_items` instead of `result`. 3. **Code organization**: Break up the function into smaller, more focused sections. This will improve readability and make it easier to understand the logic. 4. **Type hints**: Add type hints for function parameters and return types to make the code more self-documenting. **Performance Improvements** 1. **Use a more effic…
29.7s533 output tokens

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Frequently asked questions

Which is cheaper, Claude Sonnet 5.5 or Llama 3.1 8B Instruct?
Per 1M output tokens, Claude Sonnet 5.5 is ¥1,787 and Llama 3.1 8B Instruct is ¥6.72 on FastMetal (yen, before tax), so Llama 3.1 8B Instruct is cheaper.
How do the context windows of Claude Sonnet 5.5 and Llama 3.1 8B Instruct compare?
Claude Sonnet 5.5 takes 1,000,000 tokens; Llama 3.1 8B Instruct takes 131,072.
Can I use Claude Sonnet 5.5 and Llama 3.1 8B Instruct with the same API key?
Yes. On FastMetal's OpenAI-compatible endpoint, switch by passing "anthropic-claude-sonnet-5-5" or "llama-3.1-8b-instruct" 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 5.5 and Llama 3.1 8B Instruct from the browser chat and the API. No monthly fee.

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