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

# Overview

> How Charlie syncs inventory data to power fulfillment intelligence

Charlie automatically syncs your inventory data to Shopify metafields in real-time. This background process enables all inventory-based features in the app.

## Why inventory sync matters

Shopify Functions—the technology that powers checkout customization—cannot access your store's inventory data directly. Charlie bridges this gap by:

1. **Listening** to inventory changes across all your locations
2. **Syncing** quantities to metafields that Functions can read
3. **Calculating** sellable inventory (available minus safety stock)

This happens automatically with no configuration required.

## What it enables

<CardGroup cols={2}>
  <Card title="Inventory constraints" icon="ban" href="/constraints/overview">
    Block locations from fulfilling when stock is low or unavailable
  </Card>

  <Card title="Inventory routing" icon="arrow-up-right-dots" href="/order-routing/inventory-rules">
    Prioritize locations with higher stock levels
  </Card>

  <Card title="Sellable inventory" icon="calculator">
    Calculate available-to-sell quantities using safety stock reserves
  </Card>

  <Card title="Capacity tracking" icon="gauge-high" href="/order-routing/capacity-rules">
    Monitor daily order capacity per location
  </Card>
</CardGroup>

## Sellable inventory

Charlie calculates **sellable inventory** for each product-location combination:

<Note>
  **Sellable inventory** = Available inventory − Safety stock
</Note>

This ensures you never sell through your safety reserves, protecting against stockouts and fulfillment failures.

**Example:**

* Available inventory: 50 units
* Safety stock: 10 units
* Sellable inventory: 40 units

Checkout will treat this location as having 40 units available, preserving your 10-unit buffer.

## Exporting inventory data

You can export a full inventory snapshot as a CSV file delivered to your email.

The export includes every tracked variant across all locations, with columns for product details, SKU, location, available quantity, safety stock, and sellable inventory.

To export:

1. Go to **Shopify Admin → Products**
2. Click the **Charlie inventory export** action
3. Enter your email address
4. You will receive an email with a download link when the export is ready

<Tip>
  Inventory exports are useful for audits, reconciliation, and sharing inventory data with your operations team.
</Tip>

## Configure safety reserves

While inventory sync runs automatically, you can configure **safety stock** levels to control how much inventory to hold back from selling.

<Card title="Safety Stock" icon="shield" href="/inventory/safety-stock">
  Set up inventory reserves to protect against stockouts
</Card>