Best POS Systems for Ecommerce and In-Store Sales

For a business that sells online and in store, the first decision is which system masters the catalog and the orders: the ecommerce platform or the POS. Everything else, from pickup to refunds, follows from that answer. The three candidates answer it differently. The Lightspeed and WooCommerce documentation below was checked on October 7, 2026; the Shopify POS and Square descriptions rest on their published positioning.

• Shopify POS: the ecommerce platform is the master. The store sells from the same Shopify catalog and order history.
• Lightspeed: the POS is the master. Lightspeed's Retail (X-Series) documentation for its Shopify integration treats Retail POS as the system of record and warns that edits made in Shopify may be overwritten.
• Square: one vendor covers the POS and payments. For a business already running WooCommerce, WooCommerce documents a Square extension that syncs products and inventory, with a setting where the merchant picks WooCommerce or Square as the source of truth for product data, plus an order fulfillment sync that is disabled by default.

Decide who edits products

Ecommerce teams may own descriptions, images, launch timing, and online-only offers, while store teams handle receiving, counts, barcodes, and transfers. List each product field and the team that changes it, then check it against the master each candidate imposes. A mismatch is not a configuration detail: it decides which team works in which tool every day.

Apply the same test to orders and customers. Name where an online order lives, where a store sale lives, and which record customer service opens first. A shared customer view should not require store staff to hold administrator or payment privileges.

Scenario: a pickup order is only partly in stock

A customer orders three items online for pickup at a second store. When the associate prepares the order, one item cannot be found. The customer takes two items, the missing one is refunded to the original payment, and the store adjusts its stock.

Shopify POS is positioned on one commerce workflow, so confirm in the trial that the pickup order, the partial fulfillment, and the refund stay on one order record. With Lightspeed, online sales sync into Retail POS, so the buyer must confirm where partial fulfillment and the refund are performed and whether both systems then agree. With Square and WooCommerce, the extension's order fulfillment sync is disabled by default, so run the split pickup with that setting off and then on, and check each time where the partial fulfillment and the refund are recorded and whether WooCommerce and Square then agree.

Run a split-pickup test

Create a synthetic catalog with variants at two locations. Place an online pickup order for three items, fulfill two at the second store, refund the third to the original payment in approved test modes, and adjust stock. Then change one product description on the side that is not the declared master.

Check where each step happened, whether the refund reached the right payment, whether stock agrees in both systems, and which description survived. Ask ecommerce, store, and finance users to explain the order from their own screens. POS Platform Guide has not performed the test.

Edge case: one storefront still needs tax and payment answers

Shared commerce data does not establish correct sales-tax treatment. The business and qualified advisers must decide nexus, sourcing, taxability, and filing, then confirm that the configuration and exports support that policy. A shared payment provider does not prove PCI DSS compliance for every channel either; map each application, device, provider, and merchant duty through PCI SSC materials.

Conclusion

Choose Shopify POS when the online store is the center of the business and store staff can work inside its catalog. Choose Lightspeed when store operations should own products and the ecommerce team can accept Retail POS as the system of record. Choose Square when the web store runs on WooCommerce and will sync through the documented extension, and the merchant is ready to set the sync direction; for any other web platform, get Square's pairing in writing first. If the ecommerce platform has no documented route to any of the three, none of them is the right start: choose the POS that platform documents, or keep the store on its own system until one exists. In each case, keep the candidate only if the split-pickup test leaves one explainable order, refund, and stock history.