Connecting two systems that were never meant to talk

Every small business has at least one of these. A person opens two windows, reads a number out of one, and types it into the other. Maybe forty times a day. Nobody owns the process, it appears in no job description, and it has been happening for years.

The reason it survives is that the two systems were never built to talk, and the obvious fix, replacing one of them, costs more than the problem. It does not need replacing. It needs a bridge.

Four ways in, in order of preference

When someone says a tool cannot be integrated, they usually mean it has no documented API. That rules out one of four options, not all of them.

1. A real API

Best case, and more common than people think. Plenty of tools have a REST API that is barely mentioned in the marketing. Check the developer docs, check whether your plan includes API access, and check whether the vendor has a public integration with something like n8n or Make, because that usually means an API exists whether or not it is advertised.

2. Webhooks out, API in

Many tools that will not let you query them will happily push to you when something happens. A webhook receiver plus a small amount of logic covers a surprising share of real integration work, and it is better than polling because it fires on the event rather than on a timer.

3. Scheduled export and import

Unglamorous and completely legitimate. If a system can email a CSV nightly or drop one on a share, that file is an interface. A job picks it up, parses it, reconciles it and pushes it onward.

The latency is a night rather than a second. For most back-office work, nobody can tell the difference, and it is a fraction of the cost of anything else.

4. Driving the interface

Last resort, and it does work. A script logs in, navigates, and reads or enters what is needed. It is the most fragile option because any layout change breaks it, so it needs the tightest monitoring and it should never be the first thing you reach for.

But between a fragile bridge that is watched and a person doing it by hand forever, the bridge wins on cost every time.

Moving the data is the easy half

The part people underestimate is that the two systems disagree about reality, and always have. Once you connect them, that disagreement stops being invisible.

Names are spelled two ways. One system has a customer twice. Dates are day-first in one and month-first in the other, and both will happily accept the wrong one for any day below the thirteenth. One side allows a blank field the other treats as required.

Moving bad data faster is not an improvement. It is the same problem, arriving sooner and in more places.

So a real integration includes matching rules, a deduplication pass, and an explicit decision about what happens to a row that does not fit. That last one is where most projects quietly fail: the pipeline throws it away, and nobody finds out until a customer asks where their order went.

The correct behaviour is boring. Park the row, count the parked rows, and put that count somewhere a person will see it.

Which direction is the truth

Decide this before writing a line. For every field that exists on both sides, one system owns it and the other one follows.

Two-way sync without a declared owner produces the worst bug in this entire category: a value that flips back and forth between two systems every time either one runs, forever, because each side keeps correcting the other. It is hard to spot and maddening to unpick.

One-way is not a limitation. It is the design.

What this is worth

The arithmetic is unusually easy here because the work being replaced is measurable. Forty minutes a day of copying, at a loaded cost of thirty five dollars an hour, is roughly six thousand dollars a year. A bridge like this is usually a low four figure build.

The part that does not show up in that sum is the error rate. Manual re-entry produces mistakes at a rate everyone knows about and nobody measures, and each one costs somebody an afternoon.

Where to start

Pick the pair of systems where someone in your business has both windows open right now. That is the one, and it is nearly always reachable through option one, two or three.