What is the YAGNI principle?
YAGNI - You Aren't Gonna Need It
YAGNI means I should not implement functionality, abstractions or extension points until there is a real requirement for them. It helps prevent speculative complexity and keeps designs focused on current business needs. As a senior engineer, I balance YAGNI with architectural foresight: I do not build hypothetical features, but I still preserve sensible boundaries where the current requirements already justify them.
- 1
Implement real requirements rather than speculative features.
- 2
Avoid unnecessary abstractions and extension points.
- 3
Reduces code, testing and maintenance cost.
- 4
YAGNI does not mean ignoring known architectural requirements.
- 5
Combine YAGNI with good boundaries so future change remains possible without building the future prematurely.
Follow-up Questions
- YAGNI vs OCP: can they conflict?
- When should you introduce an abstraction early?
- How does YAGNI relate to premature optimization?
- Can following YAGNI too aggressively create technical debt?