Build vs Buy Software
A practical framework for deciding whether to build custom software or buy an off-the-shelf platform — and why the answer usually isn't as close as it feels.
The build-vs-buy decision gets debated like it's a coin flip. In practice, for most organizations, it isn't nearly as close as it feels in the room — the bias just runs in different directions depending on who's in that room.
The case for buying
Off-the-shelf software has already been built, tested, and improved by feedback from thousands of other customers. It comes with support, security updates, and a roadmap you don't have to fund yourself. For anything that isn't core to your competitive advantage — accounting, basic CRM, standard project management — buying is almost always the faster, cheaper, lower-risk path.
The case for building
Custom software makes sense when the workflow you need genuinely doesn't exist in the market, or when that workflow is the thing that actually differentiates your business competitively. If the software itself is the product, or the process it supports is truly unique to how you operate, an off-the-shelf tool will force you to bend your process to fit it — sometimes at real cost.
Questions that actually settle it
Is this process core to our competitive advantage, or table stakes? Table-stakes processes should almost always be bought.
Does a product already exist that does 80% of what we need? If so, the remaining 20% is rarely worth a custom build — configure around the gap instead.
Do we have the ability to maintain custom software long-term? Building is not a one-time cost. Every custom system needs ongoing maintenance, security patching, and someone who understands it after the original builder moves on.
What's the real cost of switching later? Buying is easier to reverse than building. A failed custom build is sunk cost with nothing to resell; a failed SaaS subscription is a cancelled contract.
The trap in the middle
The riskiest zone is customizing an off-the-shelf platform so heavily that you've effectively built custom software anyway, without the deliberate planning a real build deserves. If a platform needs extensive customization to fit, that's a signal worth taking seriously before committing further.
A reasonable default
Buy unless you have a clear, specific reason not to. Building is justified far less often than it's chosen — usually because building feels more in control, even when buying would get to the outcome faster and cheaper.