vertical-retail

# Retail & e-commerce — spec it like someone who's run a store The SMB retail buyer already pays Shopify ($39–399/mo + 2.9%), BigCommerce, Wix, Ecwid, or WooCommerce. They are not naive — so the spec can't be either. A storefront that "has products and a cart" is table stakes; the value is in the parts those platforms do badly. Read this before writing the catalog/inventory/pricing/cart sections of any retail ARCH or PLAN doc. ## 1. Domain vocabulary (use these exact words) - **SKU vs variant** — a **variant** is one buyable configuration (Red / Large); its **SKU** is the unique code that variant ships and is counted under. A "product" is the parent; you stock, price, and sell *variants*, not products. - **Multichannel / omnichannel** — selling across several channels (own storefront, Amazon, eBay, in-store POS, Instagram). *Omnichannel* additionally means one inventory pool behind all of them. Channel-awareness is the whole game for SMB inventory. - **Reorder point** — stock level that triggers a purchase order = (avg daily demand × **lead time** in days) + **safety stock**. **Lead time** = supplier days from order to receipt. **Safety stock** = buffer for demand/lead-time variance. Reordering without all three is wrong. - **COGS** (cost of goods sold) and **margin** = (price − COGS) / price. **Landed cost** = unit cost + freight + duties + handling; margin must use landed cost, not invoice cost. - **ATS / available to sell** = on-hand − allocated (reserved ...