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Pastebin System Design
Visual Problem Diagram
Scenario
A developer pastes a 2 MB log dump and shares the link on Slack—10,000 teammates open it in five minutes while new pastes arrive at 100/s. Reads dwarf writes 10:1, expired pastes must vanish on schedule, and public pastes need abuse controls—the interview is ID design, storage tiering, and read scaling, not syntax-highlighting trivia.
Design a Pastebin-like service where users upload text snippets and share them via short URLs. The workload is read-heavy—many views per create—and operations care about durable storage until expiration and fast reads for viral links.
You should support create/view/delete, configurable expiration, optional syntax highlighting, and public/private visibility. Be ready to explain ID generation, blob vs row storage, expiration cleanup, and how you serve 100M reads/day without hammering one database. Size limits and abuse controls are reasonable scope.
Constraints
Create paste (text, TTL, syntax type, privacy), view by ID, optional delete, expiration 10 min to never, public/private
< 100 ms p95 read, 99.9% availability, durable until expiry, max paste size enforced
10M pastes/day (~100 writes/s peak), 100M reads/day (~1K reads/s peak); ~100 GB/day storage; 10:1 read:write
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