---
title: Anthropic
description: Route Anthropic API requests through AI Gateway for observability and control.
image: https://developers.cloudflare.com/dev-products-preview.png
---

> Documentation Index  
> Fetch the complete documentation index at: https://developers.cloudflare.com/ai-gateway/llms.txt  
> Use this file to discover all available pages before exploring further. 

[Skip to content](#%5Ftop) 

# Anthropic

[Anthropic ↗](https://www.anthropic.com/) helps build reliable, interpretable, and steerable AI systems.

## Endpoint

**Base URL**

```
https://gateway.ai.cloudflare.com/v1/{account_id}/{gateway_id}/anthropic
```

## Examples

### cURL

With API Key in Request

* [ With Authenticated Gateway ](#tab-panel-6872)
* [ Unauthenticated Gateway ](#tab-panel-6873)

Terminal window

```
curl https://gateway.ai.cloudflare.com/v1/{account_id}/{gateway_id}/anthropic/v1/messages \ --header 'x-api-key: {anthropic_api_key}' \ --header 'cf-aig-authorization: Bearer {CF_AIG_TOKEN}' \ --header 'anthropic-version: 2023-06-01' \ --header 'Content-Type: application/json' \ --data  '{    "model": "claude-sonnet-4-5",    "max_tokens": 1024,    "messages": [      {"role": "user", "content": "What is Cloudflare?"}    ]  }'
```

Terminal window

```
curl https://gateway.ai.cloudflare.com/v1/{account_id}/{gateway_id}/anthropic/v1/messages \ --header 'x-api-key: {anthropic_api_key}' \ --header 'anthropic-version: 2023-06-01' \ --header 'Content-Type: application/json' \ --data  '{    "model": "claude-sonnet-4-5",    "max_tokens": 1024,    "messages": [      {"role": "user", "content": "What is Cloudflare?"}    ]  }'
```

With Stored Keys (BYOK) / Unified Billing

Terminal window

```
curl https://gateway.ai.cloudflare.com/v1/{account_id}/{gateway_id}/anthropic/v1/messages \ --header 'cf-aig-authorization: Bearer {CF_AIG_TOKEN}' \ --header 'anthropic-version: 2023-06-01' \ --header 'Content-Type: application/json' \ --data  '{    "model": "claude-sonnet-4-5",    "max_tokens": 1024,    "messages": [      {"role": "user", "content": "What is Cloudflare?"}    ]  }'
```

### Anthropic SDK

With Key in Request

* [ With Authenticated Gateway ](#tab-panel-6874)
* [ Unauthenticated Gateway ](#tab-panel-6875)

```
import Anthropic from "@anthropic-ai/sdk";
const baseURL = `https://gateway.ai.cloudflare.com/v1/{accountId}/{gatewayId}/anthropic`;
const anthropic = new Anthropic({  apiKey: "{ANTHROPIC_API_KEY}",  baseURL,  defaultHeaders: {    Authorization: `Bearer {cf_api_token}`,  },});
const message = await anthropic.messages.create({  model: "claude-sonnet-4-5",  messages: [{ role: "user", content: "What is Cloudflare?" }],  max_tokens: 1024,});
```

```
import Anthropic from "@anthropic-ai/sdk";
const baseURL = `https://gateway.ai.cloudflare.com/v1/{accountId}/{gatewayId}/anthropic`;
const anthropic = new Anthropic({  apiKey: "{ANTHROPIC_API_KEY}",  baseURL,});
const message = await anthropic.messages.create({  model: "claude-sonnet-4-5",  messages: [{ role: "user", content: "What is Cloudflare?" }],  max_tokens: 1024,});
```

With Stored Keys (BYOK) / Unified Billing

```
import Anthropic from "@anthropic-ai/sdk";
const baseURL = `https://gateway.ai.cloudflare.com/v1/{accountId}/{gatewayId}/anthropic`;
const anthropic = new Anthropic({  baseURL,  defaultHeaders: {    Authorization: `Bearer {cf_api_token}`,  },});
const message = await anthropic.messages.create({  model: "claude-sonnet-4-5",  messages: [{ role: "user", content: "What is Cloudflare?" }],  max_tokens: 1024,});
```

## OpenAI-Compatible Endpoint

You can also access Anthropic models using the OpenAI API schema through the [REST API](https://developers.cloudflare.com/ai-gateway/usage/rest-api/). Send your requests to:

```
https://api.cloudflare.com/client/v4/accounts/{account_id}/ai/v1/chat/completions
```

Specify:

```
{  "model": "anthropic/{model}"}
```

```json
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```