Reddit Experience · Sep 2025

I kept failing system design interviews until I realized the right way to approach system design round

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Interview Experience

I used to think I was doing “enough” prep for system design interviews—read Grokking, skimmed some blog posts, even memorized a few patterns. But every time I sat in a real interview (including one at

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I used to think I was doing “enough” prep for system design interviews—read Grokking, skimmed some blog posts, even memorized a few patterns. But every time I sat in a real interview (including one at Amazon), I froze. It wasn’t that I didn’t know the concepts. The problem was that I had never really explained them out loud in a structured way, under time pressure, with someone asking follow-up questions. System design is very different from solving Leetcode. You can’t brute force it. You need to: • Communicate clearly (not just think in your head). • Handle vague questions and drive the discussion. • Get feedback to know what you’re missing. I kept failing because I was preparing solo. Reading passively doesn’t translate into performance in a high-pressure interview. That’s when I started working on something different—a way to practice system design like you’re in a real interview, with discussions, live cohorts, and mock sessions. I’ve put it up as Classif ( https://classif.in/ ) and also opened a small Discord community for early users https://discord.gg/3ZhvEHYb . I don’t want this to just be another resource that people bookmark and forget. I want it to be a space where engineers actually practice, talk, and get feedback. If you’ve ever struggled with system design interviews—what do you think would actually help? More resources? Practice partners? Interview-style feedback?

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Topics

System Design