How large systems really work
System Design
The flagship track: from object-oriented foundations and design patterns to the architecture of planet-scale services, taught visually. Opens with the low-level design modules every interview loop grades.
Start with lesson 01 →LLD Foundations
LLD Foundationsfree
What Is Low-Level Design? HLD vs LLD vs DSA
Three interview rounds, three different games. Learn exactly where LLD sits, what interviewers grade, and why great engineers still fail this round.
4 min read
LLD Foundationsfree
SOLID · Single Responsibility: One Reason to Change
SRP is the most quoted and most misunderstood principle in software. Learn the "reason to change" test and apply it to a class interviewers love to hand you.
3 min read