Design patterns are still relevant in modern software development, providing stability and structure when frameworks fall short.Six design patterns have proven useful in 2025, including Memento for state snapshots and undo/redo functionality.Mediator pattern centralizes communication in complex component structures, promoting better code organization.Flyweight pattern helps optimize memory usage by reusing shared objects, particularly useful in rendering large numbers of similar elements.Command pattern encapsulates operations as objects, enabling macro recording and redo functionality in applications.Chain of Responsibility allows for modular request validation, ideal for handling complex validation flows in scalable systems.Builder pattern simplifies creating complex UI structures, commonly used in frontend development for DSLs and dynamic content generation.These design patterns offer shared language, mental models, and stability under stress when designing software systems.Understanding when to apply these patterns showcases advanced thinking in software development.While frameworks may change, these timeless patterns offer dependable solutions for common software design challenges.