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

# Anthropic

> Anthropic builds the Claude model family (Claude 3.5 Sonnet, Claude 3.5 Haiku, Claude 3 Opus) with strong emphasis on safety and nuanced reasoning.

Anthropic offers 19 models through Lava's AI Gateway, supporting Chat Completions (Native). Authentication uses x-api-key with default anthropic-version header. See the [Anthropic API docs](https://docs.anthropic.com/en/api) for provider-specific parameters.

<Info>Supports both **managed** (Lava's API keys) and **unmanaged** (bring your own credentials) mode.</Info>

## Quick Start

```typescript theme={null}
const response = await fetch('https://api.lava.so/v1/forward?u=https%3A%2F%2Fapi.anthropic.com%2Fv1%2Fmessages', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    Authorization: `Bearer ${forwardToken}`,
  },
  body: JSON.stringify({
    model: 'claude-fable-5',
    messages: [{ role: "user", content: "Hello!" }],
  }),
});
```

## Chat Completions (Native)

**Target URL:** `https://api.anthropic.com/v1/messages`

|                  |                                          |
| ---------------- | ---------------------------------------- |
| **Content Type** | `application/json`                       |
| **Streaming**    | Yes (set `stream: true` in request body) |

| Model                      | Input / 1M tokens | Output / 1M tokens |
| -------------------------- | ----------------- | ------------------ |
| claude-opus-4-1            | \$15.00           | \$75.00            |
| claude-opus-4-1-20250805   | \$15.00           | \$75.00            |
| claude-opus-4-0            | \$15.00           | \$75.00            |
| claude-opus-4-20250514     | \$15.00           | \$75.00            |
| claude-fable-5             | \$10.00           | \$50.00            |
| claude-opus-4-8            | \$5.00            | \$25.00            |
| claude-opus-4-7            | \$5.00            | \$25.00            |
| claude-opus-4-6            | \$5.00            | \$25.00            |
| claude-opus-4-5            | \$5.00            | \$25.00            |
| claude-opus-4-5-20251101   | \$5.00            | \$25.00            |
| claude-sonnet-5            | \$3.00            | \$15.00            |
| claude-sonnet-4-6          | \$3.00            | \$15.00            |
| claude-sonnet-4-5          | \$3.00            | \$15.00            |
| claude-sonnet-4-5-20250929 | \$3.00            | \$15.00            |
| claude-sonnet-4-0          | \$3.00            | \$15.00            |
| claude-sonnet-4-20250514   | \$3.00            | \$15.00            |
| claude-haiku-4-5           | \$1.00            | \$5.00             |
| claude-haiku-4-5-20251001  | \$1.00            | \$5.00             |
| claude-3-haiku-20240307    | \$0.25            | \$1.25             |

## Next Steps

<CardGroup cols={2}>
  <Card title="All Providers" icon="grid" href="/gateway/supported-providers">
    Browse all supported AI providers
  </Card>

  <Card title="Forward Proxy" icon="route" href="/gateway/forward-proxy">
    Learn how to construct proxy URLs and authenticate requests
  </Card>
</CardGroup>