Systems that do not talk to each other

How to put a yearly number on the retyping, and how to check the cheap fixes before paying for the expensive one.

Updated 19 September 2026 · 7 min read

The short answer

Somebody in your business is the integration. They keep two windows open and move figures from one into the other.

That person costs more per year than most integrations cost once. They also make mistakes late on a Friday, and the knowledge walks out with them. Before paying anybody, work out the number and check the three cheaper fixes.

Almost every business over about ten people runs more software than anybody has a full list of. The accounts package, whatever sales use, the thing the warehouse uses, a couple of spreadsheets, and an inbox that quietly holds the rest. Very little of it connects.

The gap gets filled by a person. They are competent and they are usually one of your better staff, which is part of the problem.

Work out the number before you talk to anybody

This takes five minutes and it is the only figure that matters in the conversation. Do it before a supplier does it for you.

How many hours a week go into moving the same information between two systems? Ask the person who does it rather than estimating. The answer is usually higher than the owner thinks and lower than the person doing it first claims, so take the middle.
What does that hour cost you, fully loaded? Salary, plus employer national insurance and pension, divided by working hours. For most office roles this lands somewhere between 20 and 40 pounds.
Multiply by 46 working weeks. That is the annual running cost of the gap, before anything goes wrong.
Add the cost of it going wrong. One mispriced order, one delivery to an old address, one stock figure that sent someone to a shelf that was empty. Most businesses can name last quarter examples without pausing.

Five hours a week at 30 pounds is around 6,900 a year. Ten hours is nearly 14,000. Those are the numbers to hold against any quote, and they are the reason integration work usually pays back inside two years rather than being a convenience purchase.

Four ways to join two systems, cheapest first

Work down this list. Most suppliers will start you at the bottom row.

Option	When it is right	Roughly
Leave it alone	Under an hour a week, low value per record, and a mistake is embarrassing rather than expensive.	Nothing
The connector the vendors already sell	Two mainstream products that a lot of people use together. Check this first. A surprising number of businesses pay for a custom build of something their own vendors ship.	Often included, or tens of pounds a month
An off-the-shelf automation tool	Simple rules, modest volume, and nobody gets hurt if it pauses for a day. Good for a few hundred records a month.	Tens of pounds a month
A built integration	Complicated logic, high volume, sensitive data, or a silent failure costs real money. Also the only option when one of the systems is old.	Low thousands upward

Rows two and three are not always available, and they are always worth ten minutes of checking.

The honest split is that most two-system problems at low volume belong in rows two or three. What pushes a business into row four is usually not the connection itself. It is the rules around it: this customer prices differently, that order type skips a step, these two records are the same company spelled three ways.

The question that decides the whole project

For every piece of information, which system is right when two of them disagree?

Customer address. Price. Stock figure. Order status. In most businesses the honest answer is that it depends on who you ask, which is why two reports disagree and nobody is certain which to believe. A skincare brand we worked with had Shopify, a warehouse and Xero each correct on their own and none of them agreeing.

Agreeing this is the work. Once each field has one owner, the technical side is comparatively simple. Skip it and you have built something that copies a disagreement quickly in both directions. A supplier who does not raise this in the first conversation is going to hand you that.

It is also the part with value on its own. A one-page map of where each piece of information lives, and which copy is authoritative, is frequently more useful than the integration, and several businesses stop there.

What separates one that lasts from one that does not

Integrations break. A supplier changes a field without telling anybody, a password expires, a system goes down for maintenance on a bank holiday. That is normal and it is survivable.

What is not survivable is breaking quietly. The failure mode that costs money is the one where it stops working on the 3rd, nobody notices, and the numbers stop adding up at month end. Three weeks of bad data is far more expensive than three days of no data.

It tries again before it gives up, because most failures are a network blip.
It keeps a record of what it did, so a question about one order has an answer.
It tells a named person when it cannot continue, by something that person actually reads.
It refuses to guess. Where a record is ambiguous it stops and asks rather than picking.

What it costs

One integration between two systems is the smallest piece of work we take on directly. Most land in the lowest band on the pricing page, at four to eight weeks, and the number moves mainly on how messy the existing data is rather than on the connection itself.

Hold that against the annual figure you calculated at the top. If the payback is longer than about two years, the honest position is that you should probably stay as you are for now.

Common questions

How much does it cost to connect two systems?

A connector the vendors already sell is often included in what you pay them, or costs tens of pounds a month. An off-the-shelf automation tool is similar. A built integration starts in the low thousands and rises with the complexity of the rules rather than the number of systems. Check the first two before paying for the third.

Could Zapier or Make do this instead?

For a simple connection at modest volume, often yes, and it is worth trying before commissioning anything. It stops being the right answer when the logic gets complicated, the volume gets high, the data is sensitive, or a failure that nobody notices would cost you money.

What if one of our systems has no way to connect?

There is usually another route: a scheduled export, reading the data straight from where the system stores it, or files dropped into a folder that is checked automatically. Older accounting systems installed on a company’s own server commonly work this way. A supplier should tell you plainly when a system is genuinely closed rather than sell you a workaround that breaks on the next update.

What happens when a supplier changes their software?

The integration stops, and the point of building it properly is that you find out the same day rather than at month end. It records the failure and tells a person. On a support retainer the fix is covered. Without one it is quoted as a repair.

Which system should hold the master copy of a customer?

Whichever one the people who maintain that information use daily. It is usually the accounts system for financial details and the sales system for contact details, but the right answer is the one your team will actually keep up to date, not the one that is technically tidiest.

How long does an integration take?

Four to eight weeks for a defined connection between two systems, and most of that is agreeing the rules and cleaning the existing data rather than writing the connection. Where the two systems already hold consistent records it is faster.

Tell us what is not working

Describe the process that is costing you time. If software is the wrong answer we will say so, and if a product already covers it we will name the product.

From £10,000Most projects land between £15,000 and £55,000.

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