Fundamental Principles of Good Software Design
We all love software that is both easy to use and highly functional, and once we find a well-designed software product, it spoils us for anything that falls short of those standards. Software developers are challenged to meet the requirements of their clients while keeping UX and functionality at the core of the development process. Most rely on certain guiding principles that govern software development best practices.
Software Design Principles
Software development is a complex art that can easily go haywire if developers fail to adhere to certain fundamental principles. Following are some of the most popular and useful:
SOLID is an acronym that covers five basic object-oriented programming principles used in Agile software development. Object-oriented programming breaks down a software program into basic reusable pieces of code blueprint (aka classes) that are used to improve the quality and productivity of software system design. Object-oriented programming makes it easier and less expensive to make changes to the system. It supports the reuse of code classes and simplifies the integration of components for configuring the system as a whole.

SOLID’s 5 principles are:
- Single responsibility principle (SRP): A class has only one job, and only one reason to change. A class with more than one responsibility can weaken the design and lead to damage when changes occur. The SRP principle prevents coupling of responsibilities and improves the design’s overall cohesion.
- Open/closed principle: This software principle conveys that after a class of code has been created and tested, it should be closed to modification, but open to extension. During the development process, requirements can change and new functionality may be requested. Modifying code can introduce errors into the existing code. The open/closed principle helps keep the class code fundamentally intact, while allowing for it to be extended to include new functionality.
- Liskov Substitution Principle (LSP): Under this software design principle, objects of a superclass should be replaceable with objects of its subclasses, meaning they behave in the same way. For example, if B is a subclass of A, objects of B should be able to replace objects of A without undermining the performance of the program. In other words, objects of a subclass can replace objects of the superclass without impairing the system.
- Interface segregation principle (ISP): Each class should have its own isolated interface, and class dependencies should be based on the smallest possible interface. A large and cumbersome interface with multiple class dependencies adds methods to the interface that the clients don’t need.
- Dependency inversion principle (DIP): This software principle states that high level modules should not be dependent on low level modules, and both should depend on abstractions. Abstractions in turn should not depend on details, but vice versa. The underlying premise here is that abstract interfaces and abstract classes are more stable than details, which are variable, and architectures built on abstractions are more stable than those built on details.

Other Good Software Design Principles
In addition to SOLID, there exist a few other fundamental principles that help guide the software development process:
- KISS (keep it simple stupid!): This principle has been around for decades, and has far-reaching applications for everything from human relationships to product development. The KISS principle reminds software developers to avoid complexity, and to write code that is easy to implement and maintain.
- YAGNI (You ain’t gonna need it): It is easy to get ahead of yourself, and try to implement things before you need them. This principle reminds developers to not implement functionality until it is actually needed.
- DRY (Don’t repeat yourself): As per the single responsibility principle, small pieces of code should occur only once in the entire system. This principle encourages developers to write reusable code that can be scaled and is easy to maintain.
Principled Software Design at Tateeda
The software development process is complex, and building a superior product that performs flawlessly requires deliberate and accurate adherence to basic software design principles. The experienced developers at Tateeda understand the value of tried-and-true principles, and we have made them second nature in our approach to software development. If you want a software product for your business that provides outstanding UX and trouble-free longevity, contact Tateeda today, and let’s work together to bring your project to life.