Phase 0Beginner2 of 19 in the curriculum

System Design Mindset

Learn the loop. Never memorize an answer again.

Before writing a single class or drawing a single box, you must adopt a repeatable process. Every interview problem — LLD or HLD — follows the same shape: clarify requirements, name the components, reason about data and scale, then make trade-offs out loud.

The core learning loop for every topic in this course: Learn → Close the tutorial → Explain without notes → Implement → Break it → Fix it → Explain trade-offs.

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6 topics ~60 min 6 code blocks & diagrams

Start with the first topic

0.1

What is System Design?

System design is the practice of turning a vague product idea into a concrete set of components, their interactions, and the data that flows through them — while accounting for scale, failure, and cost.

12 min practice

0.2

LLD vs HLD

Low-level design is the code view (classes, interfaces, patterns, relationships); high-level design is the system view (services, databases, queues, scaling). Both matter, and interviews start at HLD and zoom into LLD.

6 min practice

0.3

Functional vs Non-functional Requirements

Functional requirements say what the system does; non-functional requirements say how well it does it. Non-functional requirements are where system design actually happens.

8 min 1 diagram 1 code practice

0.4

Trade-offs

The most senior signal in an interview is the ability to answer 'why this and not that?' Every architectural decision is a trade-off; interviews test whether you can name the thing you gave up.

7 min practice

0.5

Numbers Every Engineer Should Know

Design decisions are only as good as the numbers behind them. Memorize a small set of latency, throughput, and size figures so you can size any system in your head during an interview.

14 min 2 code practice

0.6

The 45-Minute Interview Framework

Interviewers grade the process as much as the design. A disciplined time budget keeps you from spending 30 minutes on requirements or reaching the deep dive with no time left.

13 min 1 diagram 1 code practice