Shared inventory between a wholesale and a retail store
A wholesale store and a retail store selling the same goods is one of the oldest reasons to run two Shopify stores. It is also the case where two very different products get recommended interchangeably, so here is the honest split first.
If both stores sell the same physical units
You need shared inventory: one pool of stock, where a sale in either store immediately reduces what the other can sell. That is a real product category, and StoreTwin is not it. We copy stock numbers one way; a sale in the receiving store does not move the source store's stock, because there is no shared pool to move.
Look for apps that describe themselves as connected or pooled inventory across stores, and check one thing before buying: what happens when both stores sell the last unit within the same second. The answer separates a real pool from a fast copier.
If the two stores hold their own stock
This is the more common shape than people expect: the wholesale store ships from its own warehouse, the retail store from another, and the two never share a unit. What has to stay in step is the catalogue - products, variants, SKUs, descriptions, images, your metafields - and, per location, the numbers each store keeps for itself.
That is exactly the job StoreTwin does: one store owns the catalogue, the other receives it, and both are compared field by field every day so you find the drift before a customer does.
What differs between wholesale and retail, and stays differing
Price. Wholesale prices are not retail prices, and copying them across would be the most expensive kind of bug. StoreTwin sets a price once, when it first creates a product in the receiving store, and never touches it after that.
Who can see what. A wholesale catalogue is often narrower. You choose which products are actually synced; the rest are still compared and reported without being copied.
Stock per location. Inventory is synced per location and only for the locations you pick, so a shared warehouse can be kept in step while a store-only shelf is left alone.
How to tell which one you actually need
Ask what must happen when the wholesale store sells the last ten units. If the retail store must stop being able to sell them, you need a pool, and this is the wrong app. If the retail store has its own ten units in its own warehouse, you need the catalogues to match and the numbers to be verifiable - which is this app. The two meanings of connected inventory
If your stores hold their own stock, the free plan audits a catalogue of any size - you can see exactly what differs between wholesale and retail before paying anything.