Twinstock

Keep stock in step across your stores: a sale in one comes off the others, matched by SKU.

Free plan, paid from $14.99 a monthIn review

Twinstock is a Shopify app that keeps the stock of your own Shopify stores in step, matched by SKU. A sale, refund, restock or edit in one store comes off, or goes back on, in the others.

Link with a code: install Twinstock in each store, click Start a link in one and enter its code in the other. Each store picks the one location whose stock takes part.
See it before it syncs: once the stores are read, Twinstock counts the SKUs they share and lists those whose figures differ. You choose the store whose figures the others start from; nothing changes until you click Start syncing.
The same change, never a copied total: each store’s change is passed on as that change, so orders in two stores at the same moment both come off both. Late or repeated notices from Shopify are checked against the figures and change nothing.
New SKUs: a SKU added to one store with no stock of its own takes the others’ figure; one with a different figure waits on the SKUs page for you to pick which to keep.
Every change logged: the Changes page shows what was passed on, from which store, and when.
Pause, resume, unlink: pausing stops all changes. Resuming compares the stores again first, so nothing sold meanwhile is replayed. Unlinking or uninstalling leaves your stock as it is.

Plans

Billed by Shopify.

Free: two stores and 100 shared SKUs.
Pro: up to five stores and 10,000 shared SKUs. $14.99 a month or $149 a year, with a 7-day free trial. One store on Pro gives its whole link Pro. Your price stays the same for as long as you keep the plan; cancel any time from the app.

Good to know

SKUs are matched ignoring case and spaces at either end. A SKU on two variants of the same store is left out until only one has it, and a SKU only one store has is left alone.
Only variants that track their stock and are stocked at the store’s chosen location take part.
Twinstock syncs stock only: products, prices and orders stay each store’s own.
The Changes log keeps 30 days.

Support

Write to spyridwn.pd@gmail.com with your stores’ addresses (your-store.myshopify.com) and, if it’s about a product, its SKU.