> ## 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 Opus 5, Claude Sonnet 5, Claude Haiku 4.5) with strong emphasis on safety and nuanced reasoning.

Anthropic offers 13 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-opus-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-fable-5             | \$10.00           | \$50.00            |
| claude-opus-5              | \$5.00            | \$25.00            |
| 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-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-5            | \$2.00            | \$10.00            |
| claude-haiku-4-5           | \$1.00            | \$5.00             |
| claude-haiku-4-5-20251001  | \$1.00            | \$5.00             |

## Next Steps

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

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