🧱What LLD Actually Means
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What LLD Actually Means

Section 1 of 9

🧱What LLD Actually Means

Low Level Design (LLD) is the stage where you decide classes, methods, interfaces, and object relationships for a concrete implementation. High Level Design tells you what major components exist. LLD tells you exactly how those components behave in code.

Key points

  • LLD sits between architecture and coding
  • It focuses on maintainable object models, not infrastructure
  • Good LLD reduces rewrite work when requirements evolve
  • In interviews, clarity beats cleverness

From problem to code

  • Requirements define what the system must do
  • HLD defines services and major boundaries
  • LLD defines class contracts and interactions
  • Code implements those contracts

Pro tip: If two people can read your class model and implement the same behavior with minimal ambiguity, your LLD is in a good place.