How much does the GPT-5.6 Sol API cost?

On FastMetal, GPT-5.6 Sol is billed per token in yen: ¥893.5 per 1M input tokens and ¥5,361 per 1M output tokens, before tax. Usage is drawn from a prepaid balance; there is no subscription or monthly fee.

Can I call GPT-5.6 Sol with the OpenAI SDK?

Yes. Point base_url at https://api.fastmetal.ai/v1 and pass "gpt-5.6-sol" as the model; existing OpenAI-style code works unchanged, including streaming, tool calls and structured output.

What is the context window of GPT-5.6 Sol?

1,050,000 tokens, shared between the prompt and the response.

What do I need to try GPT-5.6 Sol?

Create an account and add credit; the model is then available both in the browser chat and over the API. There is no contract or minimum spend.

Back to Models

openai/gpt-5-6-sol

GPT-5.6 Sol

GPT-5.6 Sol is the flagship model in OpenAI's GPT-5.6 series. It is suited for complex reasoning, coding, and agentic workflows, and is particularly strong at command-line and multi-step coding tasks...

7/9/2026

1,050,000 tokens

Input: ¥893.5/M

Output: ¥5,361/M

Try in Chat Get API Key

Specifications

Modalities

Input

file

image

text

Output

text

Supported Parameters

include_reasoning

max_completion_tokens

max_tokens

reasoning

reasoning_effort

response_format

seed

structured_outputs

tool_choice

tools

Max Output Tokens

128,000

Reasoning Configuration

Default: Thinking on (effort: medium)
Selectable effort levels: max
xhigh
high
medium
low
none
Turning thinking off: Possible (reasoning.enabled: false)

How to control thinking, and what it costs

Code Examples

curl https://api.fastmetal.ai/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "gpt-5.6-sol",
    "messages": [{"role": "user", "content": "Hello!"}]
  }'

How GPT-5.6 Sol actually answers

Real responses to our standard prompts, recorded on FastMetal.

Count the number of 'r's in 'strawberry'

Count the number of 'r's in 'strawberry'. Explain your reasoning step by step.

“strawberry” can be split into letters: s, t, **r**, a, w, b, e, **r**, **r**, y The letter **r** appears **3 times**.

3.0s response78 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…

The error occurs because `users` is `undefined` when `UserList` renders, so JavaScript cannot call `.map()` on it. This often happens when data is loaded asynchronously or the parent does not pass the prop. ### Fix options **1. Give `users` a default value:** ```jsx function UserList({ users = [] }) { return ( <ul> {users.map(user => ( <li key={user.id}>{user.name}</li> ))} </ul> ); } ``` Note that this handles `undefined`, but not an explicitly passed `null`. **2. Handle missing or invalid data explicitly:** ```jsx function UserList({ users }) { if (!Array.isArray(users)) { return <p>No users available.</p>; } return ( <ul> {users.m…

7.1s response395 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):…

### Issues and suggested improvements - Move imports to module scope. - Avoid bare `except:`; it catches programming errors and interrupts such as `KeyboardInterrupt`. - Use `response.raise_for_status()` instead of manually checking only for `200`; other 2xx responses may also be valid. - Retry only transient failures, such as timeouts, connection errors, `429`, and selected `5xx` responses. Retrying most `4xx` errors is not useful. - Use exponential backoff rather than a fixed delay. - Avoid sleeping after the final failed attempt. - Replace `item["active"] == True` with `item.get("active") is True`. - Use a list comprehension for the transformation. - Add type hints and validate arguments…

33.1s response1646 output tokens

Compare these answers side by side with other models →

Frequently asked questions

How much does the GPT-5.6 Sol API cost?: On FastMetal, GPT-5.6 Sol is billed per token in yen: ¥893.5 per 1M input tokens and ¥5,361 per 1M output tokens, before tax. Usage is drawn from a prepaid balance; there is no subscription or monthly fee.
Can I call GPT-5.6 Sol with the OpenAI SDK?: Yes. Point base_url at https://api.fastmetal.ai/v1 and pass "gpt-5.6-sol" as the model; existing OpenAI-style code works unchanged, including streaming, tool calls and structured output.
What is the context window of GPT-5.6 Sol?: 1,050,000 tokens, shared between the prompt and the response.
What do I need to try GPT-5.6 Sol?: Create an account and add credit; the model is then available both in the browser chat and over the API. There is no contract or minimum spend.