80% ready, 20% yours: why configuration beats customisation
Custom code makes software fit today and break tomorrow. Configuration makes it fit and keeps it maintainable. Here is where to draw the line between the two.
Every business is different, so every business wants its software to be different. The question is how. There are two ways to make software fit: configure it or customise it. They look similar in a project plan. They are not similar three years later.
The difference
- Configuration changes settings the software was built to accept: rules, thresholds, fields, workflows, approvals. The product stays the same; it behaves differently.
- Customisation changes the product itself: new code, new tables, new screens built for one client.
Why customisation gets expensive
- Every upgrade is a project. Custom code has to be re-tested, and often rewritten, each time the product moves on.
- Knowledge leaves with people. The developers who wrote it move on; the documentation rarely keeps up.
- You stop getting improvements. A heavily customised system can't take the vendor’s new features without breaking.
- Time to value grows. Building takes months. Configuring takes weeks.
What should be the 20%
The part that is truly yours belongs in configuration:
| Yours to configure | Already built |
|---|---|
| Your data sources and field mappings | Connectors to common ERPs and banks |
| Your thresholds and tolerances | The tests and models themselves |
| Your approval routes and owners | The workflow engine |
| Your reports and value measures | The reporting layer |
When customisation is right
Sometimes it is. A process that is genuinely unique and a real source of advantage may deserve its own code. The test is simple: would you be proud to explain this difference to a competitor? If the answer is "it’s just how we’ve always done it", configure instead.
The 80/20 promise
CoSaaS keeps the line clear. The 80% is a proven library that improves for every client. The 20% is configuration that makes it yours, kept in a form we can maintain and you can understand. Read What is CoSaaS? for the whole model, or see it on the CoSaaS page.