A Systematic Approach to Low-Level Design Interviews

This article outlines a structured framework for tackling Low-Level Design (LLD) interviews. It covers several stages of the design process to help candidates create robust, scalable, and maintainable object-oriented systems. The first step is understanding requirements, clarifying assumptions, and asking key questions to ensure a clear scope. The article provides a template for documenting assumptions and defining system boundaries. The second step involves identifying entities, behaviors, and relationships in the system using the NBR (Noun-Behavior-Relationship) analysis. Key entities and their relationships are mapped out, followed by a discussion on the layered architecture design, breaking the system into four layers: Interface, Service, Manager, and Entity. The third step focuses on class design principles, including the AMPV method (Attributes, Methods, Principles, Visibility) to ensure well-structured code. Design patterns like Strategy, Factory, and Observer are also discussed, providing insights into common patterns used in LLD to solve problems efficiently. Finally, the article emphasizes designing for extensibility, testability, and maintainability, ensuring that systems can evolve over time while remaining flexible. This article is a great resource for developers preparing for LLD interview questions.