Design Dropbox

Overview–

Dropbox is a cloud-based file storage service that allows users to store and share files. It provides a secure and reliable way to store and access files from anywhere on device.

Functional Requirements–

Upload a file.
Download a file.
Automatically sync files across devices.

Out of scope–
Roll own blob storage.

Non-Functional Requirements–
Availability >> consistency.
Low latency upload and downloads. (as low as possible)
Support large files as 50gb
Reusable uploads
High data integrity. (sync accuracy)

Core Entities–
File (raw bytes)
File Metadata
Users

API–

POST /files -> Presinged Url
body: File & FileMetadata
PUT {presigned url}
Body file/chunk
PATCH /files -> 200
GET /files/:fileId -> File & FileMetadata
GET /changes?since={timestamp} -> fileIds[]

High Level Design–