System design interview questionEasyBasic System Component
Design a Pastebin
Design Pastebin: users paste text, get a short URL, and later open that URL to read the paste.
Interview scope
Client → LB/Gateway → App → DB (metadata) and Object Storage (body). Cache optional for hot reads. No Client → DB.
Functional requirements
- Create a paste and return a unique short link.
- Fetch paste content by short link.
- Optional expiry / public vs private at a high level.
Scale and quality goals
- Reads dominate writes.
- Large pastes should not live only as huge SQL rows.
- Hot pastes benefit from cache.
Capacity assumption
Design for this scale
Assume ~1M new pastes/day and ~10M reads/day (~12 RPS write, ~120 RPS read average).
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