Design Pastebin: the beginner-friendly system design interview walkthrough

System design interviews for Pastebin, CDN, and web search engines reveal critical architectural insights. Pastebin focuses on storage design for arbitrary-size content with expiration. A CDN requires a globally distributed read-through cache, prioritizing edge routing and cache invalidation. Web search engine design involves separating the crawler, indexer, and serving layer to efficiently query billions of documents. Mastering these foundational HLD patterns allows candidates to scope complex problems and address specific technical constraints effectively.