Guides

You duplicated your store. Now keep the stock honest.

Copying a store with Duplify, Matrixify or Rewind is the easy half. From the first sale the two inventories drift apart — and the three ways to stop it.

Duplicating a store is a solved problem. Matrixify (4.9 across 1,651 reviews) moves catalogues of any size by spreadsheet, Duplify (4.9 across 123) copies a store wholesale, staging tools clone environments for redesigns. An afternoon, maybe a weekend, and the second store exists — expansion store, B2B store, regional store, whatever it was for.

The part nobody warns you about starts the next morning: the two inventories begin to disagree, and they never stop.

Why the counts start lying immediately

The copy carried a snapshot of your quantities. A snapshot has no memory of where the numbers came from and no link to where they are going. From that moment:

• Every sale on either store lowers a number the other store still believes.
• Every restock raises counts in one place only.
• Every manual correction — the damaged unit you wrote off, the miscount you fixed — happens once, in one store.

If both stores sell from the same physical stock, the gap between their numbers is not a rounding error, it is overselling waiting for a customer to find it. The unit your original store just sold to its last buyer is still sitting on the duplicate store’s product page, purchasable. The mechanics of that race — and why “we’ll be careful” doesn’t close it — are covered in how overselling actually happens across stores.

First: make the copy syncable at all

Whatever method you choose next relies on one thing the duplication tools quietly preserved for you: SKUs. Every sync method matches products across stores by SKU, and a fresh duplicate is the best moment you will ever have to check them, because the catalogues are still identical.

Export products from both stores and look for two things: blank SKUs (variants that can never be matched) and duplicate SKUs (two variants sharing one identifier, so no tool can know which one you meant). Fresh duplicates rarely have mismatches — but they faithfully copy every duplicate SKU the original already had, and those become sync errors on both sides at once. The duplicate-SKU guide shows how to find every one of them in the export.

The three ways to keep the counts agreeing

1. CSV, on a schedule. Export inventory from the store you trust, import into the other. Free, and honest work the first three times. It decays predictably: the export gets done weekly instead of daily, then before holidays, then after the first oversell. Between runs the stores are wrong by exactly the amount you sold. Workable for slow catalogues, low order volume, or stores that don’t share stock — the full trade-offs are in the two-store sync guide.

2. Treat the stores as one, with Markets. If the duplicate exists only for currency, language or regional pricing, consider whether it should exist at all — Shopify Markets does those inside a single store, and one store cannot disagree with itself. This is the right answer more often than app vendors like to admit; when an expansion store is genuinely warranted is its own guide.

3. Continuous one-way sync. Nominate the store connected to reality — the one where fulfilment and restocks happen — as the one in charge, and mirror its counts into the duplicate automatically. This is what sync apps are for, and after a duplication the one-way shape is exactly right: the original already is the truth, and the duplicate should follow it. What separates the apps is not speed claims but what they do when matching is ambiguous and what they show you before writing — the choosing guide has the seven questions that separate them, and the comparison table has the whole field with their public review records.

If you go the app route: the ten-minute setup

With StockUnison the post-duplication setup is deliberately boring:

1. Install on the original store, make it the main store, and pick the location whose counts are true.
2. Connect the duplicate with the join code.
3. Match the products. On a fresh duplicate this is your quality gate: expect near-total matches, and treat every SKU flagged as a duplicate as a real defect the copy inherited — StockUnison refuses to sync those rather than guess which one you meant.
4. Stay in preview mode and read it. Every change the sync would make is worked out and logged before anything is written, so after a duplication this doubles as an audit that the copy was faithful.
5. Go live when the report is boring. From then on the duplicate follows the original within seconds, and a difference check will tell you if the two ever disagree again.

The free plan covers steps 1–4 for an unlimited catalogue — matching, preview mode, difference checks and the log — so the verification costs nothing even if you keep syncing by CSV afterwards.

Doing this for a client? Every paid plan is free to select on a development store, so the whole sync can be built and verified before the store converts — the partner program covers the rest.

One honest boundary: this keeps inventory quantities agreeing. Product edits — new items, price changes, description updates — still need Matrixify, or making the change twice. Products and prices are on the roadmap, but today the answer to “will it copy my new products across?” is no.