Connecting Accounting to Everything Else

The most common manual job in business

Someone re-types invoices from an order system into accounting, or exports a spreadsheet monthly and imports it with corrections. It is high volume, error-prone, and completely automatable.

It is also the integration with the clearest payback, because the time is measurable and the errors have a cost everyone already recognises.

Decide which system creates what

The most important decision is not technical. For each record type, one system creates it and the other receives it. Two systems both creating invoices produces duplicates that take longer to untangle than the manual process took.

One way, wherever possible

Bidirectional sync is where these projects go wrong. Two systems editing the same record produces conflicts, loops and duplicates, and the debugging is miserable.

One-way sync with a clear owner is boring and works. Bidirectional sync is interesting and generates support tickets for years.

Where information genuinely must travel both ways, split it by field: the order system owns the line items, accounting owns the payment status, and neither writes the other's fields.

Reconcile daily, not monthly

• Count invoices on both sides for yesterday, and compare
• Compare totals, not just counts — a matching count can hide a wrong value
• Report anything that failed to sync, to a person
• Keep an audit log of every record transferred, with its identifier on both sides

Finding a mismatch the next morning is a five-minute fix. Finding it at month end means reconstructing three weeks of activity, and it will happen at the worst possible time.

Handling the awkward parts

• Tax codes. The operational system's idea of VAT rarely matches accounting's exactly. Map explicitly rather than assuming.
• Rounding. Two systems rounding differently produces one-penny discrepancies that block reconciliation. Decide where rounding happens.
• Multi-currency. Agree which system sets the rate and when.
• Part payments and credits. Design these deliberately; they are where most sync errors originate.

What it costs

A one-way invoice and customer sync with a mainstream accounting package is typically £3,000–£9,000, and takes three to six weeks including a fortnight running alongside the manual process.

Against that, most businesses recover five to fifteen hours a week and a class of error that used to surface at month end. It is consistently one of the best-value projects available to a mid-sized business.

Frequently asked questions