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

# SDK Integration

> Use the LeanMCP AI Gateway in your applications with official SDKs

# SDK Integration for Developers

The LeanMCP AI Gateway works with any OpenAI-compatible SDK or library. Simply change the base URL and API key to route requests through the gateway.

<Info>
  **Key Insight**: Any library that supports a custom `baseURL` or `base_url` parameter can use the LeanMCP AI Gateway.
</Info>

## Prerequisites

<Steps>
  <Step title="Get Credits">
    Purchase credits at [leanmcp.com](https://leanmcp.com)
  </Step>

  <Step title="Create API Key">
    Create an API key at [leanmcp.com/api-keys](https://leanmcp.com/api-keys) with **SDK** permissions
  </Step>
</Steps>

## Gateway Endpoints

| Provider       | Base URL                                      |
| -------------- | --------------------------------------------- |
| **OpenAI**     | `https://aigateway.leanmcp.com/v1/openai`     |
| **Anthropic**  | `https://aigateway.leanmcp.com/v1/anthropic`  |
| **xAI (Grok)** | `https://aigateway.leanmcp.com/v1/xai`        |
| **Fireworks**  | `https://aigateway.leanmcp.com/v1/fireworks`  |
| **ElevenLabs** | `https://aigateway.leanmcp.com/v1/elevenlabs` |

***

## Official SDKs

### OpenAI SDK

<Tabs>
  <Tab title="TypeScript/JavaScript">
    ```typescript theme={null}
    import OpenAI from 'openai';

    const client = new OpenAI({
      baseURL: 'https://aigateway.leanmcp.com/v1/openai',
      apiKey: process.env.LEANMCP_API_KEY, // leanmcp_xxx
    });

    const response = await client.chat.completions.create({
      model: 'gpt-5.2',
      messages: [
        { role: 'user', content: 'Hello!' }
      ],
    });

    console.log(response.choices[0].message.content);
    ```
  </Tab>

  <Tab title="Python">
    ```python theme={null}
    from openai import OpenAI
    import os

    client = OpenAI(
        base_url="https://aigateway.leanmcp.com/v1/openai",
        api_key=os.environ.get("LEANMCP_API_KEY"),  # leanmcp_xxx
    )

    response = client.chat.completions.create(
        model="gpt-5.2",
        messages=[
            {"role": "user", "content": "Hello!"}
        ]
    )

    print(response.choices[0].message.content)
    ```
  </Tab>

  <Tab title="cURL">
    ```bash theme={null}
    curl https://aigateway.leanmcp.com/v1/openai/chat/completions \
      -H "Authorization: Bearer leanmcp_your_api_key" \
      -H "Content-Type: application/json" \
      -d '{
        "model": "gpt-5.2",
        "messages": [{"role": "user", "content": "Hello!"}]
      }'
    ```
  </Tab>
</Tabs>

### Anthropic SDK

<Tabs>
  <Tab title="TypeScript/JavaScript">
    ```typescript theme={null}
    import Anthropic from '@anthropic-ai/sdk';

    const client = new Anthropic({
      baseURL: 'https://aigateway.leanmcp.com/v1/anthropic',
      apiKey: process.env.LEANMCP_API_KEY,
    });

    const response = await client.messages.create({
      model: 'claude-sonnet-4-5-20250929',
      max_tokens: 1024,
      messages: [
        { role: 'user', content: 'Hello!' }
      ],
    });

    console.log(response.content[0].text);
    ```
  </Tab>

  <Tab title="Python">
    ```python theme={null}
    import anthropic
    import os

    client = anthropic.Anthropic(
        base_url="https://aigateway.leanmcp.com/v1/anthropic",
        api_key=os.environ.get("LEANMCP_API_KEY"),
    )

    response = client.messages.create(
        model="claude-sonnet-4-5-20250929",
        max_tokens=1024,
        messages=[
            {"role": "user", "content": "Hello!"}
        ]
    )

    print(response.content[0].text)
    ```
  </Tab>
</Tabs>

### Streaming

<Tabs>
  <Tab title="OpenAI Streaming">
    ```typescript theme={null}
    import OpenAI from 'openai';

    const client = new OpenAI({
      baseURL: 'https://aigateway.leanmcp.com/v1/openai',
      apiKey: process.env.LEANMCP_API_KEY,
    });

    const stream = await client.chat.completions.create({
      model: 'gpt-5.2',
      messages: [{ role: 'user', content: 'Write a poem' }],
      stream: true,
    });

    for await (const chunk of stream) {
      process.stdout.write(chunk.choices[0]?.delta?.content || '');
    }
    ```
  </Tab>

  <Tab title="Anthropic Streaming">
    ```typescript theme={null}
    import Anthropic from '@anthropic-ai/sdk';

    const client = new Anthropic({
      baseURL: 'https://aigateway.leanmcp.com/v1/anthropic',
      apiKey: process.env.LEANMCP_API_KEY,
    });

    const stream = client.messages.stream({
      model: 'claude-sonnet-4-5-20250929',
      max_tokens: 1024,
      messages: [{ role: 'user', content: 'Write a poem' }],
    });

    for await (const event of stream) {
      if (event.type === 'content_block_delta') {
        process.stdout.write(event.delta.text);
      }
    }
    ```
  </Tab>
</Tabs>

***

## Framework Integrations

### LangChain

<Tabs>
  <Tab title="TypeScript">
    ```typescript theme={null}
    import { ChatOpenAI } from '@langchain/openai';

    const model = new ChatOpenAI({
      modelName: 'gpt-5.2',
      configuration: {
        baseURL: 'https://aigateway.leanmcp.com/v1/openai',
        apiKey: process.env.LEANMCP_API_KEY,
      },
    });

    const response = await model.invoke('Hello!');
    console.log(response.content);
    ```
  </Tab>

  <Tab title="Python">
    ```python theme={null}
    from langchain_openai import ChatOpenAI
    import os

    model = ChatOpenAI(
        model="gpt-5.2",
        base_url="https://aigateway.leanmcp.com/v1/openai",
        api_key=os.environ.get("LEANMCP_API_KEY"),
    )

    response = model.invoke("Hello!")
    print(response.content)
    ```
  </Tab>
</Tabs>

### Vercel AI SDK

```typescript theme={null}
import { openai } from '@ai-sdk/openai';
import { generateText } from 'ai';

const customOpenAI = openai.configure({
  baseURL: 'https://aigateway.leanmcp.com/v1/openai',
  apiKey: process.env.LEANMCP_API_KEY,
});

const { text } = await generateText({
  model: customOpenAI('gpt-5.2'),
  prompt: 'Hello!',
});

console.log(text);
```

### LlamaIndex

```python theme={null}
from llama_index.llms.openai import OpenAI
import os

llm = OpenAI(
    model="gpt-5.2",
    api_base="https://aigateway.leanmcp.com/v1/openai",
    api_key=os.environ.get("LEANMCP_API_KEY"),
)

response = llm.complete("Hello!")
print(response.text)
```

***

## Adding Request Context

For better tracking and analytics, add custom headers to your requests:

```typescript theme={null}
const response = await client.chat.completions.create({
  model: 'gpt-5.2',
  messages: messages,
}, {
  headers: {
    'X-User-ID': userId,           // Track per-user usage
    'X-Session-ID': sessionId,     // Group requests by session
    'X-Request-Source': 'web-app', // Identify request source
    'X-Feature': 'chat',           // Tag by feature
  }
});
```

These headers appear in your dashboard and enable:

* Per-user usage tracking and limits
* Session-based request grouping
* Feature-level analytics
* Source attribution

***

## OpenAI-Compatible Libraries

Any library that supports a custom base URL works with the LeanMCP AI Gateway:

| Library                  | Configuration               |
| ------------------------ | --------------------------- |
| **openai** (official)    | `baseURL` parameter         |
| **anthropic** (official) | `baseURL` parameter         |
| **langchain**            | `base_url` in configuration |
| **llama-index**          | `api_base` parameter        |
| **vercel/ai**            | `baseURL` in configure      |
| **litellm**              | `api_base` parameter        |
| **guidance**             | Custom OpenAI client        |
| **instructor**           | Pass custom OpenAI client   |

### Generic Pattern

```typescript theme={null}
// Any OpenAI-compatible library
const client = new SomeAILibrary({
  baseURL: 'https://aigateway.leanmcp.com/v1/openai', // or /anthropic, /xai, etc.
  apiKey: 'leanmcp_your_api_key',
});
```

***

## Environment Setup

### Recommended: Environment Variables

```bash theme={null}
# .env file
LEANMCP_API_KEY=leanmcp_your_api_key_here
LEANMCP_OPENAI_BASE_URL=https://aigateway.leanmcp.com/v1/openai
LEANMCP_ANTHROPIC_BASE_URL=https://aigateway.leanmcp.com/v1/anthropic
```

### Multiple Environments

```typescript theme={null}
const getBaseURL = () => {
  if (process.env.NODE_ENV === 'development') {
    return 'https://aigateway.leanmcp.com/v1/openai'; // Use gateway in dev
  }
  return 'https://api.openai.com/v1'; // Direct in production (optional)
};

const client = new OpenAI({
  baseURL: getBaseURL(),
  apiKey: process.env.OPENAI_API_KEY,
});
```

***

## Error Handling

```typescript theme={null}
try {
  const response = await client.chat.completions.create({
    model: 'gpt-5.2',
    messages: [{ role: 'user', content: 'Hello' }],
  });
} catch (error) {
  if (error.status === 401) {
    console.error('Invalid API key');
  } else if (error.status === 402) {
    console.error('Insufficient credits');
  } else if (error.status === 429) {
    console.error('Rate limited');
  } else {
    console.error('API error:', error.message);
  }
}
```

***

## Benefits for Developers

<CardGroup cols={2}>
  <Card title="Unified Logging" icon="list">
    All AI requests logged in one dashboard
  </Card>

  <Card title="User Tracking" icon="users">
    Track usage per user with custom headers
  </Card>

  <Card title="Cost Attribution" icon="receipt">
    Know which features drive AI costs
  </Card>

  <Card title="A/B Testing" icon="flask">
    Test different models and prompts
  </Card>

  <Card title="Security" icon="shield">
    Block malicious users and sensitive data
  </Card>

  <Card title="Rate Limiting" icon="gauge">
    Set limits per user or globally
  </Card>
</CardGroup>

***

## Next Steps

<CardGroup cols={2}>
  <Card title="Security Features" icon="shield" href="/ai-gateway/security">
    Block users and protect sensitive data
  </Card>

  <Card title="Token Optimization" icon="chart-pie" href="/ai-gateway/token-optimization">
    A/B testing and cost reduction
  </Card>

  <Card title="Observability" icon="eye" href="/ai-gateway/observability">
    Monitor all requests
  </Card>

  <Card title="For Developers" icon="code" href="/ai-gateway/for-developers">
    Advanced developer features
  </Card>
</CardGroup>