Design REST APIs for JSON file storage
Company: Microsoft
Role: Software Engineer
Category: System Design
Difficulty: medium
Interview Round: Onsite
## Scenario
Design a service that stores **JSON files/documents** and exposes a **RESTful API** for clients.
## Requirements
- Clients can **upload**, **download**, **list**, and **delete** JSON files.
- Each file has metadata: `owner/tenant`, `fileId`, `createdAt`, `updatedAt`, `size`, and optional tags.
- Handle concurrency (simultaneous updates) and provide a way to avoid lost updates.
- Include authentication/authorization.
- Scale to many files and large aggregate storage.
## Nice-to-haves (state your assumptions)
- Versioning (keep old versions)
- Partial updates (PATCH)
- Search by metadata/tags
- Rate limiting and quotas
- Large file handling (multipart upload)
Quick Answer: This question evaluates system design and RESTful API skills for building JSON document storage, covering metadata modeling, concurrency control, authentication/authorization, scalability, and operational features such as versioning and large-file handling.