Design
Cloud File Sync Client (Dropbox-like)
Design the client-side sync engine for a cloud storage service that keeps local and remote folders in sync, handling conflicts.
This is a Low-Level Design (LLD) problem. New to LLD vs HLD? Start here.
01 - Why interviewers ask this
Sync conflict resolution is one of the hardest "small" problems in software — interviewers use it to see if you even recognize that two offline edits to the same file is a real conflict, not an edge case to ignore.
02 - Where this system exists in the real world
You interact with this design every day.
Dropbox / Google Drive / OneDrive sync clients
Enterprise file-sync and backup software
Offline-first collaborative apps
03 - What you'll master
Solve this once. Know it forever.
Detect and resolve sync conflicts
Design chunked upload for efficient re-sync
Persist a durable local change journal
04 - What you'll design
6 functional · 2 non-functional requirements.
Detect local file changes (create, edit, delete, move)
5 more requirements inside
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05 - Companies that ask this
You may face this exact question in your next interview.
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