How to sync stock between your shop and your ecommerce

The scene repeats in thousands of businesses: someone buys online an item that sold over the counter three hours earlier. Now you call the customer, apologise, refund, and collect a mediocre review. All because of one number that doesn’t reconcile between two systems.

Why stock drifts

Because the POS and the ecommerce keep separate books. Each has its own truth, and someone reconciles them by hand every day, or every week, or whenever they can. Impossible sales slip through that gap.

The principle: one source of truth

The fix isn’t syncing everything against everything, but deciding which system rules. Usually the ERP or the POS, because that’s where goods-in is recorded. Every other channel reads from it and writes its sales back to it.

It sounds obvious, but it’s the step most often skipped — and without it any integration ends in loops and mismatches.

What you need technically

• The ruling system needs an API, or at minimum scheduled automatic exports.
• A unique, stable identifier per product (the SKU) that is identical across channels.
• A middle layer translating between systems: n8n, Make or a custom connector.
• Operation logging and alerts, so you know when something stops syncing.

The SKU causes most of the trouble

Before integrating anything, check that each product carries the same code in the shop and on the website. It’s dull data-cleaning work, and it’s the number one reason integrations fail afterwards.

How often should it sync?

It depends on turnover. For products selling several times a day, real time or every few minutes. For large, slow-moving catalogues, a sync every half hour is usually enough and uses far fewer resources.

A strategy that works well: real time for the 20% of products carrying most of the sales, scheduled sync for the rest.

Common mistakes

• Syncing one way only, ERP to website, forgetting the website also sells.
• Not reserving stock while an order is in progress but not yet confirmed.
• Ignoring returns, which put units back into inventory.
• Letting the integration fail silently, with no alerts and no log.

What you gain when it works

Besides no longer selling thin air, you gain something less visible but more valuable: you can publish your entire catalogue online without fear, including lines with only a few units. Many retailers hide much of their stock online precisely because they don’t trust the number. That’s revenue left on the table.

We work on this

• IntegrationsWe synchronise stock between your shop and your ecommerce, and connect WooCommerce, Shopify or PrestaShop to your ERP, POS and CRM.
• Web development · WooCommerceWe build online stores on WooCommerce: no per-sale commission, your catalogue integrated, and built to rank.
• AutomationWe automate social posting, content and repetitive admin with n8n, Make and AI.