System design (HLD+LLD)

• There are two kinds of designs included while designing any system

  • High-Level Design (HLD)

  • Low-Level Design (LLD)

• Lets describe them in details

  • High-Level Design:

    • It includes top-level design of our entire application Like how much scalability, cost, request application can handle at a time.

      • This work is mostly done by the Principle Engineers or Product Managers

      • But in interviews, it is expected that at least the candidate should have a basic idea about these terminologies.

      • Like what are Load balancers, Caching, Compute Power, SQL vs NoSQL, Streaming, Data Modeling, etc. Few important topics are like

        • Design Twitter

        • Design Prime Music

        • Design Google Drive

        • Design Uber

        • Design Netflix

        • Design Instagram

• Low-Level Design:

  • Low-Level Design is also known as machine coding round in interviews it includes questions like design a basic crud operation of any system and then writes code for that with test cases and deployment.

  • In this round interviewer want to check your DSA knowledge as well as OOPs knowledge.

  • Suppose in the given problem like(Create a note taking app) interviewer will ask questions like how you will organize data, how to fetch data, which data structure to use and why, test cases, UML, ER Diagram, etc.

  • In organizations when any project comes then HLD is done by the PMs but the low-level design is done by the SDE-1, SDE-2. It is like breaking a big problem into smaller units and then solving it.

  • So while preparing for an interview or going for a job System Design is always very important in both places. And this comes with the practice of the questions asked in different interviews.