Build vs buy for internal tools: a decision framework
When to buy off-the-shelf software, when to configure a platform and when to build custom, with a simple framework you can apply in an afternoon.
Buy commodity software, configure a platform when it fits about eighty percent of your needs, and build custom when the workflow is your competitive edge or per-seat costs grow faster than the value. A hybrid is often best: buy the core and build only the thin layer that is uniquely yours.
Every growing company faces the same choice repeatedly: use something that exists, bend a platform to fit, or build it. The right answer changes with the tool, not with the company’s attitude to software.
When should you buy?
Email, payroll, accounting, video calls: your process is not your advantage here. Buy the best fit and adapt your habits to it.
When should you configure a platform?
If a platform covers about eighty percent of what you need and the rest is settings and fields, configure it. Watch the licence curve: costs rise with every user and every add-on.
When should you build custom software?
Build when the workflow is your competitive edge, when you need tight integration with systems no vendor supports, or when you are paying more to work around a tool than the tool is worth.
| Signal | Points toward |
|---|---|
| Standard process, many vendors do it well | Buy |
| 80% fit, differences are fields and rules | Configure |
| Unusual workflow that differentiates you | Build |
| Per-seat cost grows faster than value | Build or hybrid |
| Need to be live in days | Buy, then revisit |
The hidden costs on both sides
- Buying: integration work, migration if you leave, features you pay for but never use, and the day the vendor changes pricing.
- Building: maintenance, security updates, and the risk of depending on a single developer. Good documentation and handover mitigate this.
A hybrid is often best: buy the commodity core, and build only the thin layer that is truly yours, connected by APIs. That layer is usually small, fast to build and easy to maintain.