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

# W&B Inference

> Access open-source foundation models through W&B Weave and an OpenAI-compatible API

W\&B Inference gives you access to leading open-source foundation models through W\&B Weave and an OpenAI-compatible API.

* Using Inference you can build AI applications and agents without signing up for a hosting provider or self-hosting a model.
* Using Weave, you can trace, evaluate, monitor, and improve your W\&B Inference-powered applications.

## Try out Inference in the UI

Navigate to [https://wandb.ai/inference](https://wandb.ai/inference) to explore available models and try them out in the Weave Playground.

For more information on the web interface, see the [UI Guide](/inference/ui-guide/).

## Use Inference through the API

This Python example uses Inference to send a chat completion request to an LLM.

```python lines theme={null}
import openai

client = openai.OpenAI(
    # The custom base URL points to W&B Inference
    base_url='https://api.inference.wandb.ai/v1',

    # Create an API key at https://wandb.ai/settings
    api_key="<your-api-key>",

    # Optional: Team and project for usage tracking
    project="<your-team>/<your-project>",
)

response = client.chat.completions.create(
    model="meta-llama/Llama-3.1-8B-Instruct",
    messages=[
        {"role": "system", "content": "You are a helpful assistant."},
        {"role": "user", "content": "Tell me a joke."}
    ],
)

print(response.choices[0].message.content)
```

## Next steps

1. Set up your account using the [prerequisites](/inference/prerequisites/).
2. Review the [available models](/inference/models) and [usage information and limits](/inference/usage-limits/).
3. Use the service through the [API](/inference/api-reference/) or [UI](/inference/ui-guide/).
4. Try out supported models in the [W\&B Weave Playground](/weave/guides/tools/playground).
5. Try the [usage examples](/inference/examples/).

<Info>
  For information about pricing, usage limits, and credits, see [Usage Information and Limits](/inference/usage-limits/).
</Info>