Build or buy? How to decide between custom software and an off-the-shelf tool

We build software for a living, and we still tell people to buy something off the shelf when it is the better choice. Here is how we think about the decision.

Start with the problem, not the solution

Write down what is going wrong today and what it costs: hours of staff time each month, errors, delays, lost sales. If you cannot put a rough number on it, you are not ready to choose between building and buying, and a short conversation will usually help more than a quote.

When buying is the better answer

Buy when the process is standard and many other companies share it, such as accounting, payroll or email. Buy when the software is not part of what makes your business different, and when speed matters more than a perfect fit. A subscription that does 90 percent of the job today is often better than a custom system in six months.

When building is the better answer

Build when your process is unusual and is part of how you compete, when you keep working around a product instead of with it, or when you need to connect several systems that were not designed to talk to each other. Build when you need to control where your data lives, or when the per-user fees of a product will cost more over a few years than building and running your own.

The costs people forget

Subscriptions grow with every user and every feature tier, and moving away from one later can be slow and expensive. Custom software has costs after launch too: hosting, security updates, fixes and the small changes that every real system needs. Count both sides over three to five years, not only the first invoice.

A middle path

Often the best answer is neither. Configure an existing product, connect it to your other tools, and build only the small piece that is truly specific to you. It costs less than a full build and avoids bending your business around a generic tool.

Three questions that settle most cases

• What does the workaround cost us each month, in staff time?
• Could we export all our data and leave if we had to?
• Which part of this, if any, is something no existing product does?

If you are unsure, describe the problem to us. If an existing product fits, we will say so.