10 System Design Concepts That Took Me From Junior Dev to Senior Engineer

Disclosure: This post includes affiliate links; I may receive compensation if you purchase products or services from the different links provided in this article. After bombing my first three system design interviews at top tech companies, I made a decision: I would master system design properly, not just memorize answers. What followed was 18 months of deep study, failed attempts, successful interviews, and real production experience. The result? I went from a developer who dreaded system design questions to one who genuinely enjoys them. The turning point was mastering 10 foundational concepts that underpin every system design decision. These aren't just interview topics—they're the principles that separate engineers who build systems that survive production from those who build systems that survive demos . In this article, I'm sharing those 10 concepts with the depth and clarity I wish someone had given me years ago. Why System Design Knowledge Makes or Breaks Your Career Before div