Difference between High Level Design(HLD) and Low Level Design(LLD)

System design has two parts: High-Level Design (HLD): shows the overall plan, like a roadmap. Low-Level Design (LLD): gives detailed steps for programmers to build each part. High-Level Design (HLD) (Macro Design): HLD is the "what and why" — it gives a bird's-eye view of the entire system. You're thinking in terms of major components, how they interact, what technologies to pick, and why. It's meant for architects, stakeholders, and product managers to align on the overall direction before any coding begins. Low-Level Design (LLD) (Micro Design): LLD is the "how" — it zooms into each component and specifies exactly how it will be built. You're thinking in terms of classes, database table schemas, API contracts, method signatures, state machines, and caching keys. It's meant for developers who will actually implement the system. A simple analogy: if you're building a house, HLD is the architect's blueprint showing the number of floors, room layout, and material choices. LLD is the cont