We do not build custom software. Here is how to choose someone who does.

We build and maintain two products. We do not take on custom development, website projects or consulting engagements, and requirements that genuinely need those are requirements we turn away.

That is a deliberate narrowing rather than a gap. A company doing both tends to solve every problem with whichever of the two has capacity that month, and the customer has no way of telling which answer they received.

Custom software is the most expensive way to solve a problem and the only way to solve some. Before commissioning any, it is worth confirming that the requirement is genuinely unmet rather than unexamined.

The usual test is whether the thing you cannot do is central to how the business competes, or simply a habit that a product would ask you to change. The second is far more common, and changing the habit is cheaper than building around it.

• They ask about your operations before discussing technology. A firm that leads with a stack has not understood the problem yet.
• They will tell you which parts should be bought rather than built. A firm proposing to build everything is selling hours.
• The contract says who owns the code and the data, in plain terms. This is the single most common thing to get wrong.
• There is a written plan for handover and for what happens if the relationship ends. Bespoke software outlives the people who built it.
• They can show you something running that they built for someone else, with that customer willing to speak to you.
• They give you a maintenance figure, not just a build figure. Custom software has an ongoing cost that build quotes routinely omit.

Maintenance. A build quote is a number for delivery, and custom software then needs updating for as long as it is used: operating system changes, regulatory changes, a payment provider changing an interface.

A business that budgeted only for the build finds this out in year two, usually at the point when the original developers have moved on and whoever picks it up has to understand it first.