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

# Broadcast Engine

> Scheduling and managing bulk WhatsApp campaigns with audience precision.

The Broadcast Engine is designed for high-volume message delivery. Whether sending a weekly newsletter or a flash sale notification, the engine provides the tools to manage large-scale distribution with confidence.

## Campaign Creation

Building a broadcast follows a streamlined workflow to ensure accuracy and compliance.

### 1. Audience Selection

Select recipients from your contact database using:

* **Tags**: Target specific segments like `vip-customers` or `beta-testers`.
* **Imported Lists**: Use contacts from a recent CSV import.
* **Filters**: Combine criteria (e.g., "Tag = 'Newsletter' AND Region = 'UK'").

### 2. Audience Preview

Before sending, the **Audience Preview** tool shows you a sample of the recipients. This helps verify that your variable mappings (like `{{name}}`) are pulling data correctly from the contact records.

### 3. Template Configuration

Select an approved template and map variables to contact fields. The preview will update dynamically to show how the message looks for the selected audience sample.

## Scheduling and Sending

The Broadcast Engine supports both immediate and planned delivery.

### Schedule Picker

* **Send Now**: Immediate dispatch to the fan-out engine.
* **Scheduled Send**: Select a specific date and time in the future.
* **Timezone Awareness**: Choose whether to send at a fixed UTC time or at the recipient's local time (requires contact timezone data).

### Fan-out Engine

Our proprietary fan-out engine manages delivery at scale:

* **Rate Limiting**: Automatically adheres to your WABA's current messaging tier limits.
* **Queue Management**: Prioritizes messages to ensure timely delivery even during peak traffic.
* **Throughput Monitoring**: Real-time tracking of send success rates.

## Analytics and Reporting

Once a broadcast is live, monitor performance in the dashboard:

* **Delivery Rate**: Percentage of messages successfully accepted by WhatsApp.
* **Read Rate**: Percentage of delivered messages opened.
* **Click-through Rate**: Engagement with buttons or links.
* **Conversion Tracking**: Success against predefined campaign goals.
* **Meta Usage & Cost**: Settings → Usage estimates delivered-template Meta costs, free service-window traffic, and per-campaign spend attribution across 7-day, 30-day, and month-to-date windows.

See [Meta Usage & Cost Monitor](/operations/meta-usage-cost-monitor) for the estimate model and caveats.

## Safety Measures

* **Deduplication**: Automatically prevents sending the same broadcast to a contact multiple times within a 12-hour window.
* **Opt-out Handling**: Automatically excludes contacts who have used the "Opt-out" button on previous marketing messages.
* **Safety Preflight (opt-in)**: A workspace can require a passing `campaign_safety_audits` preflight before a campaign is allowed to launch — a hard-block severity ladder gates launch, and a recipient-set hash check refuses a launch if recipients changed since the audit ran. See [Campaign Safety Preflight](/operations/campaign-safety-preflight) for the full gate model and data shape.