> ## Documentation Index
> Fetch the complete documentation index at: https://thethirdpenco-feat-tool-lifecycle-events.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# openrouter()

> Create an OpenRouter language model

Factory function to create an OpenRouter model instance. OpenRouter provides access to many AI models through a unified OpenAI-compatible API.

## Signature

```python theme={null}
def openrouter(model_id: str, *, api_key: str | None = None) -> LanguageModel
```

## Parameters

<ParamField path="model_id" type="str" required>
  The model identifier in `provider/model-name` format (e.g., "openai/gpt-4o").
</ParamField>

<ParamField path="api_key" type="str" optional>
  OpenRouter API key. Falls back to `OPENROUTER_API_KEY` environment variable.
</ParamField>

## Returns

A `LanguageModel` instance configured for OpenRouter.

## Environment

Requires `OPENROUTER_API_KEY` environment variable.

```bash theme={null}
export OPENROUTER_API_KEY="sk-or-v1-..."
```

## Popular Models

| Model ID                             | Description                 |
| ------------------------------------ | --------------------------- |
| `openai/gpt-4o`                      | OpenAI GPT-4o               |
| `anthropic/claude-3.5-sonnet`        | Anthropic Claude 3.5 Sonnet |
| `google/gemini-pro-1.5`              | Google Gemini Pro 1.5       |
| `meta-llama/llama-3.1-405b-instruct` | Meta Llama 3.1 405B         |

## Example

```python theme={null}
from ai_query import generate_text
from ai_query.providers import openrouter

result = await generate_text(
    model=openrouter("openai/gpt-4o"),
    prompt="Hello, world!"
)
```

## Provider Options

```python theme={null}
result = await generate_text(
    model=openrouter("anthropic/claude-3.5-sonnet"),
    prompt="Be creative.",
    provider_options={
        "openai": {
            "temperature": 0.9,
            "max_tokens": 1000
        }
    }
)
```