Integration

What it means

Integration connects two systems so they exchange data by themselves: the webshop and the ledger, the bank and billing, the warehouse and the ERP, time tracking and payroll. The aim is to remove the point where a person types the same number a second time.

Technically it runs over an API, a webhook or a file exchange. At low volume a simple scheduled export is often cheaper and more reliable than a live connection.

An integration is not a one-off job but one more piece of software that needs maintaining. When one of the systems changes its format or interface, the connection stops working, often without any visible error. The more tools are wired together, the more such points there are, and unmaintained connections quickly turn into technical debt. At that point it is worth comparing them with a single system that covers more of the work.

How it works in practice

Designing one starts with questions that have nothing to do with technology: which system is the source of truth, what happens on an error, how duplicates are handled and who checks. Format and frequency come afterwards.

In accounting the payoff is largest on documents that are numerous and individually small - webshop orders, bank movements, till receipts. For paper, document digitisation remains the complement.

With a webshop using a payment gateway it often turns out that the bank receives not the order amount but a combined payout net of fees. So we set the integration up to bring a payout breakdown from the payment gateway as well: which orders it contains and what fee was deducted. Only then can payments be matched to invoices and the fee booked as a cost backed by a document.

What to watch out for

Automatically transferring badly configured data produces errors at scale that are hard to clean up afterwards. So a connection runs in parallel first, a sample is reconciled, and only then is the manual check switched off - never the other way round.

A connection often runs on an API key with full rights that someone pasted into the settings years ago, and nobody knows everywhere it is used. If it leaks, an outsider can reach the invoices and customers’ personal data. The key should carry only the permissions the integration really needs, and it is rotated when a contractor or an employee leaves.