Case In progress
Switching the Point of Sale Without Breaking the Business Behind It
A business is moving from a legacy desktop POS to Square while keeping its own back-office system — order follow-up, delivery, purchasing and commissions — running unchanged. The migration tooling is built and dry-run, and old and new systems are running in parallel on a test site ahead of a full rehearsal.
Status: In progress — cutover tooling built and dry-run; parallel test site running; full rehearsal before go-live.
The problem
The legacy POS was the source of every sale. Around it, the business had built its own web system for order follow-up, delivery, purchasing and sales commissions — all fed by a live sync from the old POS. Moving to Square meant the POS could change, but everything behind it had to keep working the next morning.
What the old system held
66,000+
products, of which only about 5,000 were active
15,000+
customers, about 3,200 active in the last two years
≈ 58,000
historical sales documents
100+
suppliers, plus open deposits, store credit and years of commission rules
What we rebuilt
- Business rules first — which document types survive, how returns and exchanges work across two systems, how deposits and store credit are closed out, how numbering continues without collisions
- Selective migration — only in-stock, active products with a supplier; only customers active in the last two years; older customers stay reachable through a one-click lookup tool
- Square → back-office sync — sales, payments and returns from Square flow back into the existing system, so delivery, purchasing and commission logic run unchanged
- Automatic ID-conflict resolution — when old and new systems claim the same internal number, the new record is renumbered everywhere it is referenced; visible numbers (invoice, customer, SKU) never change
- Legacy returns — returns on old sales automatically restock Square, creating the product if Square does not have it
- Parallel test site — a copy of the back-office system receives both the old POS feed and the Square feed, while the live system keeps running untouched
- Staff tools — invoice printing, receipts, QR codes and SMS links from the back-office system; a permission survey where six staff reviewed 97 Square permissions before roles were set
- POS set up for how the store sells — sale-term options on every item (final sale, sample sale, gift, pre-order), the list price printed on receipts when it is higher than the selling price, and staff mapped so commissions keep calculating
- Cutover plan — a written, step-by-step night-of procedure with backups, reconciliation checks and a defined rollback
Key principle Change the tool at the counter. Keep the business behind it running.
Which task takes too much time?
Tell us how your team does it today and which software and files are involved. We can work through where a tool or a different process would help.
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