# LiteLLM

LiteLLM is a Python library that gives one interface to many model APIs. Use its OpenAI-compatible route, with the exchange as `api_base`, to send requests to the exchange.

## Before you start

- A workspace with a balance and a `spend` key. See [API keys](https://inference.ai.exchange/docs/keys.md).

## 1. Export the key

```bash
export LIQUID_API_KEY=sk-liquid-...
```

## 2. Install LiteLLM

```bash
# Python 3.10 or later
pip install litellm
```

## 3. Send a request

Put `openai/` before the model name and set `api_base` to the exchange. The prefix selects the API format. The exchange auctions the model that follows it.

The `X-Title` header names the client on your receipts.

```python
import os
import litellm

response = litellm.completion(
    model="openai/liquid.auto",
    api_base="https://router.inference.ai.exchange/v1",
    api_key=os.environ["LIQUID_API_KEY"],
    extra_headers={"X-Title": "LiteLLM"},
    messages=[{"role": "user", "content": "hello"}],
)
```

To get the current model names, use `GET /v1/models`. See [Market data](https://inference.ai.exchange/docs/market.md).

## Notes

- The exchange sets a cap on each request. It is in the `x-liquid-cap-usd` response header. To limit total spend, set a spending limit on the key. See [API keys](https://inference.ai.exchange/docs/keys.md).
- To send purchasing rules, pass an `exchange` block in `extra_body`. See [Purchasing rules](https://inference.ai.exchange/docs/rules.md).

## Troubleshooting

| Symptom                                 | Cause and fix                                                                  |
| --------------------------------------- | ------------------------------------------------------------------------------ |
| `401`                                   | The key is wrong, revoked or expired. Export it again.                         |
| `404`                                   | Keep `/v1` at the end of `api_base`.                                           |
| `model_not_found`                       | The model is not on the book. Use an exact name from `GET /v1/models`.         |
| A request is refused for lack of funds. | The workspace balance cannot cover the cap. Add funds on the **Credits** page. |

See [Errors](https://inference.ai.exchange/docs/errors.md) for the error codes.

## Next steps

- [LangChain](https://inference.ai.exchange/docs/connect-langchain.md): another Python framework with an OpenAI chat model.
- [OpenAI SDK](https://inference.ai.exchange/docs/connect-openai-sdk.md): streams and purchasing rules in code.
- [Purchasing rules](https://inference.ai.exchange/docs/rules.md): models, strategy and limits, and presets.