A pre-order is a purchase made before a product is available to ship. For ecommerce sellers on Shopee, Lazada, Shopify, and TikTok Shop, pre-orders are one of the most powerful ways to validate demand, secure revenue upfront, and avoid dead stock. Instead of guessing how much inventory to order, you let real customer purchases guide your buying decisions. In 2026, pre-orders are especially important for multichannel sellers — where overselling a pre-order item on one marketplace while stock is allocated elsewhere can damage seller ratings and trigger penalties.

A SKU number (Stock Keeping Unit) is a unique alphanumeric code that ecommerce sellers use to identify, track, and manage every product in their inventory. Unlike barcodes or UPCs assigned by manufacturers, SKUs are custom-created by your business — giving you full control over how products are organised across Shopee, Lazada, Amazon, Shopify, and your warehouse.