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

# Authentication

> Learn how to authenticate with the SmartLead API

## Overview

SmartLead API uses API keys for authentication. Your API key carries many privileges, so be sure to keep it secure!

## Getting Your API Key

<Steps>
  <Step title="Login to SmartLead">
    Visit [app.smartlead.ai](https://app.smartlead.ai) and log in to your account
  </Step>

  <Step title="Navigate to Settings">
    Click on your profile icon and select "Settings" → "API Keys"
  </Step>

  <Step title="Generate New Key">
    Click "Generate New API Key" button
  </Step>

  <Step title="Copy and Store Securely">
    Copy the generated API key and store it securely. This key will not be shown again.
  </Step>
</Steps>

<Warning>
  API keys are equivalent to your password. Never commit them to version control, share them publicly, or expose them in client-side code.
</Warning>

## Using Your API Key

### Query Parameter Method (Recommended)

Pass your API key as a query parameter in the URL:

```bash theme={null}
GET https://server.smartlead.ai/api/v1/campaigns/?api_key=YOUR_API_KEY
```

### Request Body Method

For POST/PATCH requests, you can also include the API key in the request body:

```json theme={null}
{
  "api_key": "YOUR_API_KEY",
  "name": "My Campaign"
}
```

## Example Requests

<CodeGroup>
  ```bash cURL theme={null}
  curl -X GET "https://server.smartlead.ai/api/v1/campaigns/?api_key=YOUR_API_KEY" \
    -H "Content-Type: application/json"
  ```

  ```python Python theme={null}
  import requests

  API_KEY = "YOUR_API_KEY"
  BASE_URL = "https://server.smartlead.ai/api/v1"

  # Using query parameter
  response = requests.get(
      f"{BASE_URL}/campaigns/",
      params={"api_key": API_KEY}
  )

  campaigns = response.json()
  ```

  ```javascript JavaScript theme={null}
  const API_KEY = 'YOUR_API_KEY';
  const BASE_URL = 'https://server.smartlead.ai/api/v1';

  async function fetchCampaigns() {
    const response = await fetch(
      `${BASE_URL}/campaigns/?api_key=${API_KEY}`,
      {
        headers: {
          'Content-Type': 'application/json',
        },
      }
    );
    
    const data = await response.json();
    return data.campaigns;
  }
  ```

  ```php PHP theme={null}
  <?php
  $api_key = 'YOUR_API_KEY';
  $base_url = 'https://server.smartlead.ai/api/v1';

  $ch = curl_init();
  curl_setopt($ch, CURLOPT_URL, "$base_url/campaigns/?api_key=$api_key");
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
  curl_setopt($ch, CURLOPT_HTTPHEADER, array(
      'Content-Type: application/json'
  ));

  $response = curl_exec($ch);
  curl_close($ch);

  $data = json_decode($response, true);
  ?>
  ```
</CodeGroup>

## Authentication Errors

If your API key is invalid or missing, you'll receive a 401 Unauthorized response:

```json theme={null}
{
  "success": false,
  "error": {
    "code": "UNAUTHORIZED",
    "message": "Invalid or missing API key"
  }
}
```

## Best Practices

<AccordionGroup>
  <Accordion title="Store API Keys Securely">
    * Use environment variables or secure key management systems
    * Never hardcode API keys in your source code
    * Rotate your API keys periodically
  </Accordion>

  <Accordion title="Use Environment Variables">
    ```bash theme={null}
    # .env file
    SMARTLEAD_API_KEY=your_api_key_here
    ```

    ```python theme={null}
    import os
    API_KEY = os.getenv('SMARTLEAD_API_KEY')
    ```
  </Accordion>

  <Accordion title="Handle 401 Errors Gracefully">
    Always check for authentication errors and handle them appropriately in your application.
  </Accordion>
</AccordionGroup>

## Rate Limiting

Your API key is subject to rate limiting based on your subscription plan. See [Rate Limits](/guides/rate-limits) for more information.

## Multiple API Keys

You can generate multiple API keys for different applications or environments:

* **Production Key**: For your live application
* **Development Key**: For testing and development
* **Integration Keys**: For specific third-party integrations

<Tip>
  Generate separate API keys for different environments to better manage access and track usage.
</Tip>

## Regenerating API Keys

If you suspect your API key has been compromised:

1. Log in to your dashboard
2. Navigate to Settings → API Keys
3. Click "Regenerate" next to the compromised key
4. Update your application with the new key

<Warning>
  Regenerating an API key will immediately invalidate the old key. Make sure to update all applications using the old key.
</Warning>

## What's Next?

<CardGroup cols={2}>
  <Card title="Create a Campaign" icon="rocket" href="/api-reference/campaigns/create">
    Learn how to create your first campaign via API
  </Card>

  <Card title="Add Email Accounts" icon="envelope" href="/api-reference/email-accounts/add-smtp">
    Set up your sending email accounts
  </Card>
</CardGroup>