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

# Overview

> Anthropic API authentication, endpoints, and supported models

## Base URL

```
https://api.pipellm.ai
```

## Authentication

| Header              | Value              |
| ------------------- | ------------------ |
| `x-api-key`         | `$PIPELLM_API_KEY` |
| `anthropic-version` | `2023-06-01`       |

## Endpoints

| Type      | Endpoint                                  |
| --------- | ----------------------------------------- |
| Messages  | `POST /v1/messages`                       |
| Streaming | `POST /v1/messages` (with `stream: true`) |

## Supported Models

**Claude Sonnet 4.5** (Latest, recommended)

* `claude-sonnet-4-5-20250929` / `claude-sonnet-4-5-latest`
  * Best for complex agents and coding
  * 200K context window

**Claude Haiku 4.5**

* `claude-haiku-4-5-20251015` / `claude-haiku-4-5-latest`
  * Fastest and most cost-effective

**Claude 3.7 Series**

* `claude-3-7-sonnet-20250219` / `claude-3-7-sonnet-latest`
  * Hybrid reasoning with Extended Thinking

For the complete model list, see the [Claude Models documentation](https://docs.anthropic.com/en/docs/about-claude/models).

## Next Steps

<Columns cols={2}>
  <Card title="Messages" icon="code" href="/api-reference/anthropic/messages">
    Endpoint reference and SDK examples
  </Card>

  <Card title="Tool Use" icon="wrench" href="/api-reference/anthropic/tool-use">
    Function calling
  </Card>

  <Card title="LangChain (Anthropic)" icon="link" href="/integrations/langchain-anthropic">
    Framework integration guide
  </Card>

  <Card title="Claude Code" icon="terminal" href="/integrations/claude-code">
    Coding tool integration
  </Card>
</Columns>