Interfaces

The feature that separates flexible code from maintenance nightmares.

✖️ The Problem
Stop hard-coding your Business Central dependencies. When you declare a specific codeunit variable instead of using an interface, you’re creating a rigid coupling that’s difficult to undo. Build for flexibility today, or you’ll be rewriting your logic in six months.

🛠️ The Fix
Interfaces – Shifts focus from implementation to intent. This informs the system what needs to happen without dictating how it happens. This is the secret to building Business Central solutions that will survive versions upgrade and changing requirements.
It is interesting to note, while interfaces add a layer of abstraction, they significantly reduce the Cyclomatic Complexity of your functions by removing giant CASE statements or IF-THEN-ELSE ladders used to switch between providers.

Why this matters
✅ Scalability – Swap or add payment providers without touching a single line of your core engine.
✅ Testability – Use mock codeunits to simulate API responses. No more hitting live APIs or dealing with “Sandbox down” issues during your automated test runs.
✅ Solid foundation – This is the open/closed principle in action. This ensures the solution is built to last not just to work.

💡 The Bottom Line
Hard-coding says: “I hope requirements never change.” Interfaces says: “Bring on the change, the architecture is ready.