“We must connect Kingdee / Yonyou / SAP” often lands in the brief on day one. Finance wants to stop typing vouchers. The owner wants one connected system. The floor still changes prices on a sheet and releases outbound in WeChat. If operations documents are wrong, you connect wrong documents. An interface is an amplifier, not a cleaner.
When you can wait to connect
Phase one is to walk intake, stock, and outbound correctly. Finance keeps the current software and exports a statement from the operations system at month-end. That is not backward. It lowers cutover risk. Finance-only with stock still on sheets flips the problem. See What happens if you only go live with finance and skip inventory. ERP first vs. custom modules is in Should a mid-size company buy ERP first, or start with custom modules.
When you must connect
Volume is high and month-end vouchers cannot be typed in time; the group requires inventory and revenue to follow ERP; customer statements must follow the finance period. Then connect — but draw the interface box. Do not “auto-sync because both sides have a customer module.” Master data has one owner: write which side wins for customer codes, item codes, and warehouses. If both sides can edit, reconcile never matches. Sales and finance seeing the same contract is the operations premise. See Sales and finance looking at the same customers and contracts.
Write push timing too: outbound immediately, or after finance review; how credit notes, returns, and price changes reverse. Failure cannot be one popup. You need a queue, a log, and a manual retry. Audit asks who released which document on which day. See what the system does at reconcile and audit. The interface only matters if order-to-cash can align invoicing. See From order to cash: how a system cuts one more fight.
Integration stretches the cycle. Price it on its own
Whether the other system has an open API, whether fields line up, and whether a test company exists can turn “write a push” into “wait on their implementer.” That belongs in the quote. See What a custom business system costs and how long it takes. If a packaged ERP already sits unused, connecting first freezes a bad flow. See A packaged ERP nobody uses is almost as bad as having none. DaXi Technology can launch the operations system alone, then write order and stock results back to finance or the current ERP. To decide whether to connect, go to the Business systems service page and say which finance software you run and whether an implementer is already on site.
The connection must reconcile. Posted docs reverse with a credit
A connection is not a one-time success. Account changes, period close, and their upgrade can make the interface fail silently in some month. You need a reconcile report: how many documents pushed today, how many failed, whether amounts line up. The most common accident: the finance period is closed and operations still edits the document. The rule must be “posted cannot change — reverse with a credit.” Parcel, SMS, and payments can connect too, but they rank below outbound and vouchers. Phase one that connects one direction and one document type is easier to accept than ten interfaces at once. Test red and blue documents at real amount scale in their test company. A Postman 200 is not acceptance. Put the implementer’s contact on the project roster. When the interface hangs, your team should not guess their fields alone.