> ## Documentation Index
> Fetch the complete documentation index at: https://docs.laozhang.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# GPT-6.1 Sol API launch: pricing and usage

> GPT-6.1 Sol (gpt-6.1-sol) is live on LaoZhang API. Get the model ID, standard and long-context prices, how it differs from GPT-6 Sol, and API examples.

GPT-6.1 Sol is OpenAI's newer Sol model, positioned as near-Astra performance for complex coding and professional work at a lower cost. On LaoZhang API it has the same input and output prices as `gpt-6-sol`, and half the cache-read price.

* **Published**: October 13, 2026
* **Last verified**: October 13, 2026
* **Status**: Active; available in the `default` token group

## Key facts

| Item | Details |
| - | - |
| Model ID | `gpt-6.1-sol` (Chat Completions returns the snapshot `gpt-6.1-sol-2026-09-29`) |
| OpenAI release date | September 29, 2026 |
| Available on LaoZhang API | In the public pricing configuration as of October 5, 2026 |
| Endpoints | Base URL `https://api.laozhang.ai/v1`; Chat Completions `POST /v1/chat/completions`, Responses `POST /v1/responses` |
| Token group and billing | `default` group, usage-based (per token) |
| Price | \$2 input and \$10 output per 1M tokens, the same as OpenAI's Standard rates; long-context rates are in [Pricing](#pricing) |
| Context length (OpenAI) | 1,050,000-token context window, with up to 922,000 input tokens and 128,000 output tokens |
| Tool calling | Requires the Responses API |

## Pricing

These rates come from LaoZhang API's public pricing as of October 13, 2026, in US dollars per 1M tokens. They match the Standard rates on [OpenAI's pricing page](https://developers.openai.com/api/docs/pricing).

| Rate | Standard | Long context |
| - | -: | -: |
| Input | \$2 | \$4 |
| Output | \$10 | \$15 |
| Cache read | \$0.1 | \$0.2 |
| Cache write | \$2.5 | \$5 |

Requests with up to 272K input tokens use the standard rates. Once a request has more than 272K input tokens, the whole request is billed at the long-context rates. For current rates, see the [model and pricing catalog](/en/models) and the [console pricing page](https://api.laozhang.ai/account/pricing).

## How it differs from GPT-6 Sol

| | `gpt-6.1-sol` | `gpt-6-sol` |
| - | - | - |
| Input / output (standard) | \$2 / \$10 | \$2 / \$10 |
| Cache read (standard) | \$0.1 | \$0.2 |
| `reasoning_effort` in Chat Completions | `low`, `medium` (default), `high`, `xhigh` | `none`, `low`, `medium` (default), `high`, `xhigh`, `max` |
| Function calling in Chat Completions | Not supported; use Responses | Supported when `reasoning_effort` is `none` |

* Workloads that resend a long prefix, such as long system prompts, multi-turn chats, and agents, pay less overall because cache reads cost half as much.
* If your requests use `none` or `minimal`, switch to `low` and compare the results. For `max`, use the Responses API.
* Sampling parameters work only when reasoning effort is `none`, which GPT-6.1 Sol doesn't support, so always remove them:
  * `temperature`, `top_p`
  * `logprobs`, `top_logprobs`

## Call GPT-6.1 Sol

Create an API key in [Token management](https://api.laozhang.ai/token) in the `default` group, with its billing mode set to Usage first (按量优先, recommended) or Usage-based (按量计费). Then export the key in your terminal:

```bash theme={null}
export LAOZHANG_API_KEY="replace-with-your-LaoZhang-API-key"
```

These examples send one message to `gpt-6.1-sol` through Chat Completions and through Responses. For Python, run `python -m pip install openai` first.

<Tabs>
  <Tab title="Chat Completions">
    ```bash theme={null}
    curl https://api.laozhang.ai/v1/chat/completions \
      -H "Authorization: Bearer $LAOZHANG_API_KEY" \
      -H "Content-Type: application/json" \
      -d '{
        "model": "gpt-6.1-sol",
        "messages": [
          {"role": "user", "content": "Explain a database index in three sentences."}
        ]
      }'
    ```
  </Tab>

  <Tab title="Responses">
    ```bash theme={null}
    curl https://api.laozhang.ai/v1/responses \
      -H "Authorization: Bearer $LAOZHANG_API_KEY" \
      -H "Content-Type: application/json" \
      -d '{
        "model": "gpt-6.1-sol",
        "input": "Explain a database index in three sentences."
      }'
    ```
  </Tab>

  <Tab title="Python">
    ```python theme={null}
    import os
    from openai import OpenAI

    client = OpenAI(
        api_key=os.environ["LAOZHANG_API_KEY"],
        base_url="https://api.laozhang.ai/v1",
        timeout=300.0,
        max_retries=0,
    )
    response = client.responses.create(
        model="gpt-6.1-sol",
        input="Explain a database index in three sentences.",
    )
    print(response.output_text)
    ```
  </Tab>
</Tabs>

* In Chat Completions, the reply text is in `choices[0].message.content`.
* In Responses, the text is in the `output` item whose `type` is `message`; the Python SDK joins it in `response.output_text`.
* Token usage and the charge for each request are in [call logs](https://api.laozhang.ai/log).

## Who is affected

* **Affected**: projects that call text models through LaoZhang API's OpenAI-compatible endpoint. An API key in the `default` group with the Usage first or Usage-based billing mode can call it.
* **Not affected**: existing models. `gpt-6-sol`, `gpt-6-astra`, and `gpt-6-luna` remain available, and current integrations need no changes.

## Frequently asked questions

### I already use GPT-6 Sol. Do I need to switch?

No. Both models have the same input and output prices, and GPT-6.1 Sol's cache reads cost less. If you plan to switch, compare quality, latency, and token usage on representative requests, then adjust reasoning effort and tool calling as described above.

### Why does a Chat Completions request with tools return 400?

GPT-6.1 Sol doesn't support function calling in Chat Completions. Send the request to `POST /v1/responses` and pass `tools` in the Responses API format.

### Why does `reasoning_effort: "max"` return an error?

In Chat Completions, GPT-6.1 Sol goes up to `xhigh`. For `max`, use the Responses API and set `reasoning.effort`.

### How are requests with more than 272K input tokens billed?

The whole request is billed at the long-context rates, not just the tokens above 272K: input and cache rates double, and output rates rise 1.5×, the same rule OpenAI uses.

## Sources and related links

* [OpenAI API changelog](https://developers.openai.com/api/docs/changelog): the September 29, 2026 entry for GPT-6.1 Sol
* [GPT-6.1 Sol model page](https://developers.openai.com/api/docs/models/gpt-6.1-sol): context window, maximum output, reasoning effort, endpoints, and tools
* [OpenAI API pricing](https://developers.openai.com/api/docs/pricing): standard and long-context rates
* [GPT-6 Astra, Sol, and Luna launch](/en/announcements/gpt-6-launch-2026-09)
* [Use OpenAI models with LaoZhang API](/en/api-reference/openai)
* [Model and pricing catalog](/en/models)
* [Latest announcements](/en/changelog)


This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.