Design Instacart Inventory System

Instacart runs a grocery delivery service. Customers build an order online, and dedicated shoppers fulfill those orders by visiting store locations. Among these locations, certain facilities operate as "dark stores" — retail spaces closed to the general public, stocked by a partner, and used exclusively by Instacart’s picking workforce. This problem concerns the inventory system that powers one such dark store: it tracks what’s physically on the shelf, what’s already…