Turn out-of-stock products into revenue without the risk of overselling. Holdline enforces pre-order limits natively through Shopify checkout — no fragile scripts, no leftover code. Tag orders instantly for warehouse/3PL fulfillment, and get alerted the moment stock is back so you can end pre-orders in one click. Isolated virtual inventory keeps your real warehouse counts untouched. Built on Online Store 2.0 Theme App Extensions — clean install, clean uninstall.

• Enforces strict pre-order limits natively through Shopify checkout.
• Clean OS 2.0 Theme Block that integrates seamlessly with no ghost code.
• Dual-shield order tagging for seamless warehouse and 3PL fulfillment routing.
• Detects restocked inventory, switch back to regular sales with 1 click.
• Keeps pre-order limits in an isolated location, apart from real warehouse stock