SKU

SKU stands for Stock Keeping Unit. It's the seller's internal ID for a specific configuration of a specific product — the level at which inventory is actually counted.

A red XL t-shirt and a red M t-shirt are two SKUs, even if they share a parent listing. If you have 5 colours and 4 sizes, that's 20 SKUs.

Robnu uses your SKU on every internal record — packing slip, vendor invoice, customer invoice, manifest line, deduction trace. When you graduate to an OMS for inventory, you'll bring the same SKU IDs with you; nothing in Robnu's data model needs to change.