Why inventory drifts between Square and Shopify
Square and Shopify each keep their own counts. A sale on one side does not change the other side unless something copies the number across. After a quiet Tuesday you might not notice. After a Saturday you do.
The online store still shows three left. The shelf is empty because those three walked out through Square. Or the website sold the last unit, and the register rings it up anyway. That is an oversell, and it is an undersell in the other direction when you hide a product that the other system still has.
CSV is the usual patch. Export Square, export Shopify, stare at a spreadsheet, import the winner. It works once. It fails when two people edit the file, when a location column is skipped, or when the next rush starts before the import finishes. Sync Square and Shopify inventory by making the count a repeating job with a map, not a hero spreadsheet.
If you are still asking whether the platforms can coexist at all, start with Does Shopify work with Square?.
What “inventory sync” means here
Location pairs
A location pair is one Shopify location mapped to one Square location. Downtown’s Shopify stock syncs with Downtown’s Square stock. The warehouse syncs with the warehouse. You are not pouring every store into a single company-wide number.
That 1:1 map is the whole idea. If two stores share one Shopify location, they will share one count, and the floor will look wrong. Name the locations so a person can tell them apart before you pair them.
Counts copied from your primary store
When stock changes on the store you chose as primary, SquareFloww copies that on-hand count to the paired location. On Starter you run the copy. On Growth and Pro you can let it run automatically after you turn it on.
Products still have to be linked, by SKU or by title, or there is no item to attach the count to. Catalog linking is covered in Sync Shopify and Square products.
The store whose count gets copied
Choose Shopify or Square as the store whose on-hand count SquareFloww copies to the other side. If the floor counts the shelf every morning in Square, choose Square. If Shopify is where you receive purchase orders, choose Shopify. Set that before a sale event.
Unmapped locations do not join this rule. Their counts stay local. Map every place you sell from, or accept that the leftover location will drift.
Setup flow for inventory sync
Connect Shopify and Square
Install SquareFloww and authorize Square. The install steps are on How to connect Square to Shopify. Inventory sync has nothing to align until that connection exists.
Map every selling location you care about
Pair active stores first. Leave closed pop-ups unmapped on purpose, and write that down so nobody “fixes” them later. Starter allows one pair. If you have a second selling location, you need Growth or Pro before that second count can stay aligned.
Confirm products are linked
A quantity cannot sync onto the wrong item. Check that the SKU or title match is the same physical product. Spot-check a fast seller and a slow seller. Fix mismatches before you sync the whole catalog.
Run inventory sync
You can sync the stock you select, or the linked items at the locations you mapped. A product import or export can copy stock for those items at the same time. On Starter, run sync and then read the counts on a handful of SKUs in both admins. On Growth or Pro, turn automatic sync on once that check looks right. The activity log shows what each sync did. The plan and positioning page is Shopify Square integration.
Manual vs automatic inventory sync
| Plan | Price | Location pairs | Sync mode | Products | Customers |
|---|---|---|---|---|---|
| Starter | $19/mo | 1 | Manual | 1,000 | 500 |
| Growth | $39/mo | 3 | Automatic | 2,000 | 2,000 |
| Pro | $79/mo | Unlimited | Automatic | 10,000 | 10,000 |
Manual sync is honest work. Someone runs it on a schedule you can keep: before open, after a delivery, before a promotion. It is a fit when you have one location and the catalog is not moving every hour.
Automatic sync is the fit when staff will not reliably run that job, or when you have up to three locations on Growth. Pro removes the pair cap and raises the product and customer caps to 10,000. The 7-day trial is on every plan, so you can prove one pair before you pay for automatic.
A practical checklist before you trust the counts
Use this before a launch, a holiday weekend, or a new store opening.
- Map every location that can sell or fulfill today.
- Leave dead locations unmapped, and tell the team they are unmapped.
- Link products by SKU where you have codes. Use title only where the names are unique.
- Set the source of truth and do not change it mid-promotion.
- Run one manual sync and compare five known SKUs in both admins.
- If nobody owns the “press sync” job, move to Growth or Pro for automatic sync.
- Re-check the map when you add a location. A new store does not join by itself.
With the map set and the primary store chosen, the other store shows that store’s on-hand count after sync. A receiving process and a cycle count still belong to the store you copy from.
Multi-location retailers
One pair is a single store. The moment you have a second address, you are in multi-location inventory, and the Starter cap is the constraint. Growth covers three pairs with automatic sync. Pro covers unlimited pairs.
Do not collapse two stores into one Shopify location just to stay on a smaller plan. You will hide which store is empty. The longer treatment is Multi-location inventory with Shopify and Square.
Inventory sync vs product sync vs customer sync
They ship in the same app. They are not the same job.
| Job | What moves | Where to read |
|---|---|---|
| Inventory | On-hand counts per location pair | This page |
| Products | Title, description, price, image | Sync Shopify and Square products |
| Customers | Buyer profiles, both ways | Sync customers between Shopify and Square |
Syncing a price does not sync a quantity. Syncing a quantity does not copy order history. If you only need stock, you still link products so the count has an item to land on.