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

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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.

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What it enables

Inventory constraints

Block locations from fulfilling when stock is low or unavailable

Inventory routing

Prioritize locations with higher stock levels

Sellable inventory

Calculate available-to-sell quantities using safety stock reserves

Capacity tracking

Monitor daily order capacity per location

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Sellable inventory

Charlie calculates sellable inventory for each product-location combination:
Sellable inventory = Available inventory − Safety stock
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.

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Configure safety reserves

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

Safety Stock

Set up inventory reserves to protect against stockouts