> ## Documentation Index
> Fetch the complete documentation index at: https://agno-v2-studio-tools-doc.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Fallback Routing

> Use fallback models with OpenRouter's dynamic model routing.

OpenRouter's dynamic routing supports fallback models. If the primary model fails due to rate limits, timeouts, or unavailability, OpenRouter tries fallback models in order.

## Prerequisites

Set OPENROUTER\_API\_KEY environment variable.

```python theme={null}

from agno.agent import Agent
from agno.models.openrouter import OpenRouterResponses

# ---------------------------------------------------------------------------
# Create Agent
# ---------------------------------------------------------------------------

agent = Agent(
    model=OpenRouterResponses(
        id="openai/gpt-oss-20b",
        # Fallback models if primary fails
        models=[
            "openai/gpt-oss-20b",
            "openai/gpt-4o",
        ],
    ),
    markdown=True,
)

agent.print_response("Write a haiku about coding", stream=True)

# ---------------------------------------------------------------------------
# Run Agent
# ---------------------------------------------------------------------------

if __name__ == "__main__":
    pass
```

## Run the Example

```bash theme={null}
# Clone and setup repo
git clone https://github.com/agno-agi/agno.git
cd agno/cookbook/90_models/openrouter/responses

# Create and activate virtual environment
./scripts/demo_setup.sh
source .venvs/demo/bin/activate

# Export relevant API keys
export OPENROUTER_API_KEY="***"

python fallback.py
```