# Claude API

**Provider:** Anthropic
**Category:** ai
**Base URL:** `https://api.anthropic.com/v1`
**Auth:** api-key — `x-api-key: sk-ant-api03-...
anthropic-version: 2023-06-01`
**Rate Limit:** 2,000 RPM · 160,000 TPM (default)
**Free Tier:** No
**Pricing:** Pay per use (pay-as-you-go)
**Docs:** https://docs.anthropic.com

## Description

Anthropic's Claude API provides access to the Claude 4.x family of models. Claude Sonnet 4.6 is ideal for most tasks; Claude Opus 4.6 handles the most complex reasoning; Claude Haiku 4.5 is fastest and most affordable. All models support extended context windows, vision inputs, tool use, and computer use. Batch API (50% off) and prompt caching (90% off cached inputs) are available.

## Endpoints

| Method | Endpoint | Description |
|--------|----------|-------------|
| POST | `https://api.anthropic.com/v1/messages` | Send a message and receive a response |
| POST | `https://api.anthropic.com/v1/messages (streaming)` | Stream response tokens as SSE |
| GET | `https://api.anthropic.com/v1/models` | List available Claude models |

## Authentication

Pass your Anthropic API key in the x-api-key header. Also include the anthropic-version header.

```
x-api-key: sk-ant-api03-...
anthropic-version: 2023-06-01
```

## Sample Request

```bash
curl https://api.anthropic.com/v1/messages \
  -H "Content-Type: application/json" \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -d '{
    "model": "claude-3-5-sonnet-20241022",
    "max_tokens": 1024,
    "messages": [
      {"role": "user", "content": "What is the capital of France?"}
    ]
  }'
```

## Sample Response

```json
{
  "id": "msg_01XFDUDYJgAACzvnptvVoYEL",
  "type": "message",
  "role": "assistant",
  "content": [{
    "type": "text",
    "text": "The capital of France is Paris."
  }],
  "model": "claude-3-5-sonnet-20241022",
  "stop_reason": "end_turn",
  "usage": {
    "input_tokens": 14,
    "output_tokens": 10
  }
}
```

## Pricing Details

Claude Haiku 4.5: $1/M input, $5/M output. Claude Sonnet 4.6: $3/M in, $15/M out. Claude Opus 4.6: $5/M in, $25/M out. Batch API: 50% off. Prompt caching: 90% off cached inputs.

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*Source: [API Map](https://apimap.dev/apis/anthropic/) — CC BY 4.0*