How much does it cost to connect two business systems?

What you are really paying for

An integration project is rarely just "writing the connection". The price usually covers five things: working out exactly what should happen, building it, testing it with realistic data, going live safely, and looking after it afterwards. Suppliers who quote only for the build tend to come back later for the rest, so ask what each of the five includes.

Six things that move the price

1. Whether the systems are built to be connected

Modern software usually offers a proper interface for other programs to talk to. Older systems may not, which means a workaround such as reading files they produce or working at database level. Workarounds are possible, but they take longer and need more care.

2. Which way the data flows

Sending orders in one direction is simple. Keeping stock levels, prices and customer details in step in both directions is a different job, because the two systems must agree on which is right when they differ.

3. The state of your data

Duplicate customers, missing fields and inconsistent product codes are the most common cause of overruns. Cleaning data before the build is far cheaper than discovering the problem halfway through.

4. What happens when something goes wrong

A robust connection retries failed messages, alerts a person and never silently loses an order. That care costs more than a quick script, and it is the difference between a connection you can trust and one you have to watch.

5. Testing

Real orders, awkward cases (refunds, part shipments, out-of-stock items) and a safe way to go live all take time. Testing is where a good supplier earns their fee.

6. Support afterwards

Software suppliers change their systems. Connections need updating when they do, so ask who looks after it and what that costs.

Two versions of the same job

Illustrative example: A business wants its web shop connected to its accounts system. In version one, the shop and the accounts package are both modern, product codes already match, and the only requirement is to send each paid order across once. That is a small, well-defined job that suits a fixed fee. In version two, the business also wants stock levels and prices to flow both ways across three warehouses, the order system is twenty years old with no interface, and product codes differ between systems. Same sentence ("connect the shop to the back office"), but a far bigger job, best split into stages and run on time and materials against an agreed budget.

How the work is priced

We use two models, depending on how well the job can be defined:

• Fixed fee for defined jobs, where the scope is clear and the risk is low. You know the cost before we start.
• Time and materials for larger or more complex work, where requirements will evolve. We agree a budget up front and report against it regularly, so there are no surprises.

The trade-offs are explained in more detail in fixed fee or time and materials?

Questions to ask any supplier

1. What exactly is included, and what is not?
2. What happens if either system changes its interface?
3. How will we know if an order fails to transfer?
4. Who owns the code and the documentation?
5. What does support cost once it is live?
6. What assumptions is this price based on, and what would change it?

Ways to keep the cost down

• Clean your data first. Agree one code per product and remove obvious duplicates.
• Start with one flow. Connecting orders first, then stock, then shipping spreads the cost and proves the value early.
• Be clear about the rules. Decide in advance what should happen for a refund, a cancellation or an out-of-stock item.
• Have one decision maker. Waiting for answers is a hidden cost on any project.

What to have ready for a first conversation

The names of the two systems, what you want to flow between them, roughly how many orders or records a day, and what goes wrong today. That is enough for a useful, honest estimate. If you are still deciding what to connect, our guide to the hidden cost of re-keying data shows how to put a figure on what the current manual work costs, which helps you judge whether a quote is good value.

Common questions