> ## 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.

# Update Campaign Schedule

> Configures when and how frequently campaign emails are sent.

<Note>
  Configures when and how frequently campaign emails are sent Sets timezone (IANA format), sending hours (start/end in 24-hour format), active days of week (0=Sunday through 6=Saturday), and minimum time between consecutive emails (in minutes)
</Note>

## Overview

Configures when and how frequently campaign emails are sent

**Key Features**:

* Validates timezone string and time format before saving

## Path Parameters

<ParamField path="campaign_id" type="number" required>
  The ID of the campaign to update
</ParamField>

## Query Parameters

<ParamField query="api_key" type="string" required>
  Your SmartLead API key
</ParamField>

## Request Body

<ParamField body="schedule" type="object" required>
  Sending schedule configuration

  <Expandable title="Schedule Object">
    <ParamField body="timezone" type="string" required>
      IANA timezone (e.g., "America/New\_York", "Europe/London")
    </ParamField>

    <ParamField body="days" type="array" required>
      Days of week to send (0=Sunday, 1=Monday, ..., 6=Saturday)

      Example: `[1, 2, 3, 4, 5]` for Monday-Friday
    </ParamField>

    <ParamField body="start_hour" type="string" required>
      Start sending time (24-hour format, e.g., "09:00")
    </ParamField>

    <ParamField body="end_hour" type="string" required>
      Stop sending time (24-hour format, e.g., "17:00")
    </ParamField>

    <ParamField body="min_time_btw_emails" type="number">
      Minimum minutes between consecutive emails
    </ParamField>
  </Expandable>
</ParamField>

<RequestExample>
  ```bash cURL theme={null}
  curl -X POST "https://server.smartlead.ai/api/v1/campaigns/123/schedule?api_key=YOUR_API_KEY" \
    -H "Content-Type: application/json" \
    -d '{
      "schedule": {
        "timezone": "America/New_York",
        "days": [1, 2, 3, 4, 5],
        "start_hour": "09:00",
        "end_hour": "17:00",
        "min_time_btw_emails": 120
      }
    }'
  ```

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

  API_KEY = "YOUR_API_KEY"
  campaign_id = 123

  schedule = {
      "schedule": {
          "timezone": "America/New_York",
          "days": [1, 2, 3, 4, 5],  # Monday-Friday
          "start_hour": "09:00",
          "end_hour": "17:00",
          "min_time_btw_emails": 120  # 2 hours between emails
      }
  }

  response = requests.post(
      f"https://server.smartlead.ai/api/v1/campaigns/{campaign_id}/schedule",
      params={"api_key": API_KEY},
      json=schedule
  )
  ```

  ```javascript JavaScript theme={null}
  const API_KEY = 'YOUR_API_KEY';
  const campaignId = 123;

  const schedule = {
    schedule: {
      timezone: 'America/New_York',
      days: [1, 2, 3, 4, 5],
      start_hour: '09:00',
      end_hour: '17:00',
      min_time_btw_emails: 120
    }
  };

  const response = await fetch(
    `https://server.smartlead.ai/api/v1/campaigns/${campaignId}/schedule?api_key=${API_KEY}`,
    {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify(schedule)
    }
  );
  ```
</RequestExample>

## Response Codes

<ResponseField name="200" type="Success">
  Request successful
</ResponseField>

<ResponseField name="400" type="Bad Request">
  Invalid request parameters or malformed request body
</ResponseField>

<ResponseField name="401" type="Unauthorized">
  Invalid or missing API key. Check your authentication.
</ResponseField>

<ResponseField name="404" type="Not Found">
  The requested resource (campaign, lead, email account, etc.) does not exist or you don't have access to it
</ResponseField>

<ResponseField name="422" type="Validation Error">
  Request validation failed. Check parameter types, required fields, and value constraints.
</ResponseField>

<ResponseField name="429" type="Rate Limit Exceeded">
  Too many requests. Please slow down and retry after the rate limit resets.
</ResponseField>

<ResponseField name="500" type="Internal Server Error">
  Server error occurred. Please try again or contact support if the issue persists.
</ResponseField>

<ResponseField name="503" type="Service Unavailable">
  API is temporarily unavailable or under maintenance. Please try again later.
</ResponseField>

<ResponseExample>
  ```json 200 - Success theme={null}
  {
    "success": true,
    "data": {
      "message": "Schedule updated successfully",
      "schedule": {
        "timezone": "America/New_York",
        "days_of_week": [1, 2, 3, 4, 5],
        "start_time": "09:00",
        "end_time": "17:00",
        "min_time_between_emails": 120
      }
    }
  }
  ```

  ```json 401 - Unauthorized theme={null}
  {
    "message": "Invalid API Key"
  }
  ```

  ```json 404 - Not Found theme={null}
  {
    "error": "Resource not found"
  }
  ```

  ```json 422 - Validation Error theme={null}
  {
    "error": "Invalid parameters provided"
  }
  ```
</ResponseExample>

## Schedule Best Practices

### Business Hours

Send during recipient's business hours:

* **B2B**: 9 AM - 5 PM local time
* **B2C**: 10 AM - 8 PM local time
* **Global**: Consider multiple timezones

### Days of Week

```
Monday-Friday [1,2,3,4,5]  - Best for B2B
Tuesday-Thursday [2,3,4]    - Highest open rates
All 7 days [0,1,2,3,4,5,6] - For B2C or urgent campaigns
```

### Time Between Emails

* **120+ minutes**: Appears more natural
* **60-120 minutes**: Moderate pacing
* **30-60 minutes**: Aggressive (use carefully)

<Tip>
  Longer delays between emails (2-3 hours) result in better deliverability and appear more natural to recipients.
</Tip>

## Common Timezones

* `America/New_York` - US Eastern
* `America/Los_Angeles` - US Pacific
* `America/Chicago` - US Central
* `Europe/London` - UK
* `Europe/Paris` - Central Europe
* `Asia/Tokyo` - Japan
* `Asia/Dubai` - UAE
* `Asia/Kolkata` - India
* `Australia/Sydney` - Australia

[See full list of timezones](https://en.wikipedia.org/wiki/List_of_tz_database_time_zones)

## Implementation Details

Schedule timezone must be valid IANA timezone. Start/end hours in 24-hour format. Min time between emails prevents rapid-fire sending.

**Response Format**: object

## Related Endpoints

* [Get Campaign by ID](/api-reference/campaigns/get-by-id)
* [Update Campaign Settings](/api-reference/campaigns/update-settings)
* [Update Campaign Status](/api-reference/campaigns/update-status)