Job inventory-shopify-stock-out-of-step-with-connected-system · revised 11 October 2026
Bring Shopify stock levels back in line with the system you sync them with
For an agreed set of products at one location, Shopify stock matches your other system under a written rule, proved on a test store and a copy of the other system, with a test sale reducing both once.
You might be seeing
- Shopify shows stock that the other system says you do not have
- Stock goes back up after a sale, as if the sale was erased
- Counts differ at one location but match at another
- A fix by hand works until the next sync runs
No passwords, keys, card details or admin invites needed to start.
What usually happened
Shopify keeps stock per product variant at each location, in states such as available and committed. A sync that writes absolute numbers can overwrite sales made in between, one that targets the wrong location changes the wrong count, and one that reads only part of the stock picture mixes sellable and committed units, so the two systems drift apart each run.
Who it’s for: Owner or operations lead of a Shopify store that syncs stock with a spreadsheet, automation or script you control, and whose numbers have drifted apart.
Usually starts when: You oversold an item, or a stock count in Shopify no longer matches your warehouse system, and the gap grows with each sync.
The result: For the products and the one location you agree, Shopify available stock equals the other system's sellable stock under a written rule, a repeat run changes nothing, and a test sale on the test store reduces the test store and the copy of the other system once each.
Check whether this job fits
Five questions, about two minutes. Your answers stay on this page unless you choose to email them.
Checks you can run yourself
Compare one product by hand
Pick three products that are wrong and note their Shopify available quantity and the other system's sellable quantity.
Look for: Whether the gap is constant, grows with each sync, or matches the number of open orders.
Check the location the sync writes to
Open the sync settings and note the location it updates, then open that location in the Shopify inventory view.
Look for: A sync that writes to a different location from the one that sells the product.
What you get
- A reconciliation sheet: product, location, Shopify quantity, other system quantity, rule applied, difference
- The corrected sync logic or mapping on your copy, with a written description of the rule
- A note naming why the numbers drifted, such as absolute writes, wrong location or committed stock
- Steps to apply the change to the live sync and to put the previous one back
Included
- One sync between one Shopify store and one other system, whose logic you own and can change
- The mapping of products, variants and locations between the two systems, and the rule for which system is authoritative
- A reconciliation of an agreed set of products at one location, with every difference explained
- Correcting the sync logic on a copy pointed at a test store and at a copy or sandbox of the other system, then repeat-run, test-sale and timing checks
Not included
- Bugs inside a paid connector app that you cannot change
- Building a new warehouse or ERP integration
- A physical stock count or deciding the true quantity
- Cleaning product and SKU data across both systems
- Stock for stores that sync more than one location, unless quoted as a larger scope
How we know it’s done
Agreed with you before work starts. Each check produces evidence you keep.
After the corrected copy of the sync runs once, with the test store and the copy of the other system loaded from the agreed exports, Shopify available stock equals the other system's sellable stock under the written rule for the agreed products at the agreed location
Evidence: The reconciliation sheet with zero unexplained differences
A second sync run with no sales leaves every quantity unchanged
Evidence: Quantities before and after the repeat run
A test sale placed on the test store reduces the test store's stock and the copy of the other system's stock by the quantity sold, once
Evidence: Both quantities before and after, and the order number
With the copy of the sync held between its read and its write, a test sale is placed and the sync is released; it rejects or adjusts the stale write, so the sale is not overwritten
Evidence: Both quantities and timestamps at each step, from the timing check
Sign-off. You review the reconciliation and test results and sign off before payment. Applying the corrected sync to your live store is a separate step you take.
If it fails. If the checks do not pass, you do not pay, and we hand over what we found so anyone can continue.
When it fits, and when we stop
It fits when
- You own the sync logic: a spreadsheet, an automation you built or a script you hold
- You can make a copy of the sync and point it at a test store
- You can provide a copy or sandbox of the other system for the copy of the sync to write to, or a read-only export of it plus a test target; no test writes to your live system
- The test store can take a test order without a real payment
- The two systems share a product identifier, such as a SKU, and you can export stock from both
- You can say which system is authoritative for stock, or accept the rule we propose
We stop and tell you if
- The sync is a paid connector whose internals you cannot see or change
- Product identifiers do not match between the two systems for most of the sample
- Nobody can decide which system is authoritative
- No copy or sandbox of the other system can be set up, so a test would have to write to your live stock
- The test store cannot take a test order without a real payment
- The drift comes from stock being changed by a third system that we cannot see
What could go wrong
The previous sync logic is kept and described in the handover, so you can restore it, and the handover says to export stock from both systems before applying the change.
Scroll the table sideways to read it all.
| Risk | How we handle it |
|---|---|
| The corrected sync overwrites live stock with a stale number | The logic compares before writing, the first live run is limited to a few products, and you export both stocks first. |
| A test changes real stock in your live other system | Tests write only to the test store and to a copy or sandbox of the other system; if none can be set up, the job does not start. |
| Stock events are missed because change notifications cannot be relied on to arrive every time | The design includes a periodic reconciliation pass, as Shopify's documentation recommends. |
| Keys or customer data are sent to us | We ask for stock and product columns only, with secrets removed, and delete the files after sign-off. |
A second reviewer checks the reconciliation arithmetic, that the sync cannot overwrite a newer sale and that no store key is in any file we hold.
How we deliver
We arrange the work and independent review, then show you the result against the agreed checks. You keep authority over your systems.
- Read the sync description and the two exports, and agree the product set, location and authoritative system
- Reconcile the sample and explain every difference, separating sellable, committed and other states
- Find why the numbers drift: absolute writes over newer sales, wrong location, partial reads or missed events
- Correct the logic on the copy, preferring changes that compare before writing, and run it against the test store and the copy of the other system, both loaded from the agreed exports
- Run the copy of the sync twice with no sales, then place a test sale on the test store, and record both quantities each time
- Run the timing check: hold the copy between its read and its write, place a test sale, let it resume, and record both quantities with timestamps
- Independent review, then hand over the sheet, logic and steps; you apply them to the live sync
This is a one-off job, not emergency cover or a subscription. We confirm eligibility, the total price, a start window and a delivery date before you accept. Work starts only after agreed inputs, secure access, any licences and necessary permissions are in place. Platform, app and supplier charges are excluded unless the written quote includes them. No charge or booking is created by an enquiry.
Need to keep it working?
Discuss ongoing monitoring of this sync as a separate standing agreement.
Ongoing work is separately scoped and quoted: no monitoring, response-time guarantee or automatic subscription is included in this job.
Explore an ongoing engineering lane, or mention the responsibility you need in your enquiry.
What you can check
This is a new service. We have not delivered this job for a client yet.
Other ways to get this done
- If the other system is not authoritative, a one-way sync from Shopify to it, with a daily reconciliation report, is often simpler than a two-way one.
- Shopify documents the quantity states and the difference between setting and adjusting stock; reading that first helps decide which writes your sync should use.
Questions
Do you need my Shopify keys?
No. We work on copies pointed at a test store you own and at a copy of your other system. You apply the corrected logic to the live sync.
Can you tell me the true stock?
No. A physical count is yours. We make the two systems agree under a rule you choose.
What if I use a paid connector?
Then its bugs are the vendor's to fix. We can still review your numbers, but this fixed job needs sync logic you control.
Send an enquiry
Send us
- A description of the sync: what runs it, how often and in which direction
- A small stock export from each system for the same time, with no customer data
- The location in Shopify that the sync is meant to update
- Examples of products that are wrong, with the numbers in each system
- Whether a copy or sandbox of the other system can be made
- When the drift began and what changed around then
Later, once you agree
- A copy of the sync logic and its configuration, with secrets removed, and a test store you own
- A copy or sandbox of the other system (or a read-only export plus a test target) that the copy of the sync can write to; nothing is written to your live system
- Exports of the agreed products from both systems at one time
- A named person who confirms the authoritative system and the agreed set of products
- A company-controlled secure handoff agreed before access: no live passwords, keys, private code or customer records by ordinary email.
You keep the live store, the other system and all keys. We work on a copy of your sync pointed at a test store and at a copy or sandbox of the other system, never your live store or live system, and you apply the corrected logic to the live sync.
Email fallback: open your mail app
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