Skip to main content
Safety stock lets you hold back a portion of your inventory from being sold. This creates a buffer that protects against stockouts, fulfillment delays, and unexpected demand spikes.
Sellable inventory = Available inventory − Safety stockCustomers only see sellable inventory at checkout, ensuring your reserves stay protected.

Why use safety stock

Prevent stockouts

Keep a buffer for walk-in customers, B2B orders, or emergency restocks

Account for shrinkage

Compensate for damaged items, theft, or inventory discrepancies

Handle demand spikes

Protect against sudden increases in order volume

Support store operations

Reserve stock for in-store displays, samples, or promotions

How to access

Safety stock is managed in Charlie → Settings → Safety stock.
Safety stock in Charlie settings

Safety stock mode

When safety stock is enabled, choose how Charlie should behave when inventory reaches the safety threshold:
Safety stock mode options
ModeBehavior
Prefer other locationsDeprioritize the location but allow overflow when needed. Orders can still be fulfilled if no other option exists.
Block ordersExclude the location entirely when inventory reaches safety stock. Hard block—no orders assigned.
Use Prefer other locations for a soft approach that maximizes fulfillment. Use Block orders when you absolutely need to protect reserves (e.g., retail floor stock).

Two ways to configure safety stock

Safety stock can be managed at two levels depending on your needs. Create rules in the Charlie app to apply safety stock across products, collections, and locations in bulk. Go to Charlie → Settings → Safety stock → Add rule.
Safety stock rule configuration
1

Name your rule

Give the rule a descriptive name (e.g., “Holiday season buffer”, “Retail floor reserve”).
2

Choose reserve type

TypeDescription
Fixed quantityReserve a specific number of units (e.g., 10 units)
Percentage of inventoryReserve a percentage of available stock (e.g., 5%)
3

Set the amount

Enter the number of units or percentage to reserve.
4

Define which products

Target products using:
  • All products — applies globally
  • Specific collections — select one or more collections
  • Specific products — select individual products
5

Define which locations

Filter locations using:
  • All locations
  • Location type (Warehouse, Store, etc.)
  • Location tags
  • Specific locations
6

Activate the rule

Set the status to Active and save.

2. Product or variant overrides

For granular control, set safety stock directly on a product or a specific variant. Overrides take priority over rules. Priority: variant override → product override → rules. Go to Shopify → Products → [Product] to set a product-level override (applies to every variant), or open a specific variant for a variant-level override.
Safety stock on variant page
This view shows:
  • Available — current inventory at all locations
  • Safety — total safety stock reserved
  • Sellable — available minus safety stock
  • Fulfillable — quantity that can be assigned to orders
  • Available for purchase — whether the variant can be sold
Overrides are for exceptions. For bulk configuration, use rules in the Charlie app.

Channel displays

When safety stock is enabled, you can enforce sellable inventory across your sales channels. These settings are now managed on a dedicated page. Go to Charlie → Settings → Inventory display to configure channel displays.

Online store

Two features work together to protect against overselling:
FeatureWhat it doesProtection type
Cart blockPrevents checkout when cart exceeds sellable inventoryHard protection
Theme integrationShows accurate sellable stock on storefront pagesSoft protection
Use both features together for complete protection. Cart block catches edge cases where displayed stock may be stale.

Cart block

Cart block validates the cart at checkout against your sellable inventory. If a customer tries to check out with more items than are sellable, the order is blocked with an error message. To enable cart block:
  1. Go to Charlie → Settings → Inventory display
  2. Under Online store, click Enable next to Cart block
  3. Confirm in Shopify’s checkout settings to enable the cart validation
What happens when cart block is triggered: A customer adds 12 units to their cart, but only 10 are sellable (due to safety stock). At checkout, they see:
“This item is not available in the requested quantity”
The order cannot proceed until the quantity is reduced.
Cart block requires safety stock to be in Block orders mode. A warning appears on the Inventory display page if cart validation is enabled but safety stock is not set to Block.

Theme integration

Theme integration displays accurate sellable inventory on your storefront pages. For setup instructions, see Theme integration.

Point of Sale

Shows sellable stock to staff when viewing products in the POS app. This prevents store associates from selling through your safety reserves. To enable POS display, go to Charlie → Settings → Inventory display and activate the POS extension under Point of Sale.
Enable POS display so store staff see true sellable inventory, not just available stock.

Examples

A fashion retailer wants to ensure stores always have items on display.Rule setup:
  • Reserve as: Fixed quantity → 2 units
  • Applies to: All products
  • At locations: Location type → Store
Result: Every store keeps 2 units of each product off limits for online orders.
An electronics retailer wants extra buffer during peak season.Rule setup:
  • Reserve as: Percentage of inventory → 10%
  • Applies to: Specific collections → “Holiday Bestsellers”
  • At locations: All locations
Result: 10% of bestseller inventory is held back across all locations during the holidays.
A retailer wants different safety stock levels by location type.Rule 1 — Warehouses:
  • Reserve as: Fixed quantity → 5 units
  • At locations: Location type → Warehouse
Rule 2 — Stores:
  • Reserve as: Fixed quantity → 15 units
  • At locations: Location type → Store
Result: Stores have higher reserves for walk-in customers; warehouses stay lean.

Best practices

Start conservative

Begin with higher safety stock and reduce as you learn demand patterns

Use rules for scale

Configure safety stock via rules, not variant by variant—easier to maintain

Consider lead times

Locations with longer replenishment cycles need higher safety stock

Enable POS display

Let store staff see sellable inventory to avoid overselling reserves

Troubleshooting

Safety stock may be set too high, reducing sellable inventory to zero.Check: Compare safety stock to available inventory on the variant page. Reduce if sellable is zero but available is positive.
Changes should be immediate, but there may be a sync delay.Try: Wait 1-2 minutes for sync to complete, then refresh the checkout page.
When multiple rules match a product-location combination, Charlie uses the highest safety stock value.

Theme Integration

Display sellable inventory on your storefront

App integrations

Wire product feeds, search, and filter apps

Metafields reference

All Charlie metafields and namespaces

Inventory Overview

How Charlie syncs inventory data
Last modified on May 11, 2026