Design Reddit (Discussion Platform) - Frontend System Design Interview Guide
Design a production-ready discussion platform like Reddit with nested comments, voting, subreddits, real-time updates, and infinite scroll.
Backend as Black Box: Assume you have APIs for posts, comments, votes, and real-time updates. Focus on the frontend architecture.
Interview Approach
System design interviews are collaborative discussions where you work with the interviewer to explore different approaches and trade-offs. There are no single "correct" answers—instead, focus on:
- Asking clarifying questions to understand requirements and constraints
- Discussing trade-offs for different architectural approaches
- Starting with high-level design before diving into implementation details
- Considering edge cases and how to handle them gracefully
- Thinking about scalability and performance from the start
Important: In real interviews, you won't have enough time to cover all trade-offs in detail. We'll discuss some key trade-offs relevant to this problem (like nested comment rendering, voting strategies, etc.), but for comprehensive trade-off analysis, refer to the dedicated trade-offs section in the guidebook.
For more guidance on approaching system design interviews, see the introduction section in the sidebar.
Full system design walkthrough
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