KISS principle
KISS – "keep it simple, stupid" – is a design principles that states that simplicity should be a primary goal of design. It’s a reminder to reach for the simplest solution that meets the requirement, and a check against the urge to over-engineer.
KISS is not specific to software. It originated in aerospace engineering and has been adopted across design, communication, and management. In software it is a counterweight to accidental complexity, which is the complexity that comes from the choices a system’s designers made, rather than from the problem itself. Every abstraction, indirection, and speculative feature is a form of accidental complexity.
Simplicity in this sense is not the same as being simplistic. A simple solution can still be sophisticated. The goal is the minimal abstraction that meets the need, not the shallowest one. The principle constrains the design space, not the quality bar.
Like any principle, KISS misleads when applied dogmatically. "Simple" is a judgment relative to an audience and a context, and what is simple to one reader is opaque to another. The principle is most useful as a question – "is there a simpler thing that would work here?" – rather than as a license to cut corners.