Custom software is a program built for one business instead of sold to thousands. That's the definition and it's not very useful, because it describes a $2,000 script and a $2,000,000 platform equally well.
So here's what it usually looks like at the size most businesses buy it, and how to tell whether you're one of them.
What actually gets built
Almost none of it is exotic. The commonest builds are small, plain and specific.
- An internal tool. A screen your team uses to do a job that currently lives in a spreadsheet, a whiteboard and a group chat.
- A join between two systems. Your booking software and your accounting software, passing information without anybody retyping it.
- Something for your customers. A portal where they see their own jobs, invoices or documents without emailing to ask.
- A quoting or pricing tool. Your rules, your price list, and a document out the other end.
- An automation with judgement in it. Paperwork read and filed, enquiries sorted, records checked.
Each one is shaped like the business it was built for.
What you get that you don't get off the shelf
- It fits the process you run. Off-the-shelf software makes you run the process it was designed around, which is usually fine and occasionally expensive.
- You own it. The code, the data, the accounts. Nobody can change the price, change the terms, or close it down.
- It does the one thing you need. Not forty features you'll never open.
- The cost doesn't scale with headcount. Per-seat pricing punishes you for growing.
What you give up
Worth being straight about, because these are real and they're the reason most businesses shouldn't build.
- Somebody else's development budget. A product with ten thousand customers has more people improving it than you can afford.
- It being ready today. Buying takes an afternoon. Building takes a scoping conversation and a build.
- Being one of many. When something breaks in a product with ten thousand users, somebody else has already reported it.
- Somebody to maintain it. Software isn't a one-off purchase in the way a van is. It needs occasional attention.
Who should build, and who shouldn't
Buy something off the shelf when your process is ordinary. Accounting, payroll, email, most CRM work, most booking, most e-commerce. Thousands of businesses need what you need and somebody has already built it better than a bespoke version would be.
Consider building when one of these is true, and be honest with yourself about whether it really is.
- Nothing on the market fits, and you've looked properly. Not "nothing is perfect". Nothing fits.
- Your process is the advantage. If how you do it is why customers choose you, software that forces you into somebody else's way of working costs you the advantage you're selling.
- You're paying per seat and it hurts. At a certain head count the arithmetic flips.
- Two systems don't talk and somebody retypes between them. The commonest and cheapest reason to build anything.
What it costs
Custom software here starts at $5,000, with a fixed price agreed before the build begins. Automation on its own is often less. Larger or more custom projects are quoted separately.
You'll see wildly different numbers elsewhere and most of them are useless, because "custom software" covers a two-week integration and a two-year platform. A number quoted without a description of what it buys tells you nothing.
There's also a running cost. Hosting is usually a few dollars to a few tens of dollars a month depending on what it does, and you should budget something for changes, because a business that stops changing its software has usually stopped changing.