Google · System design 1 of 1

How would you design a file storage and sync service?

Requirements, consistency choices, metadata design, sync conflicts, and reliability.

Practice question: an editorial practice prompt, not a claim that Google asks this exact question. Interviews vary by role, level, team, and location.

How to approach this question

A focused three-stage walkthrough

  1. 1
    Scope

    Scope files, devices, sharing, and consistency.

  2. 2
    Design

    Separate blob storage from metadata and change tracking.

  3. 3
    Stress-test

    Explain upload, sync, conflict, and recovery paths.

System design framework

Make every architecture choice traceable

Scope

Clarify users, core operations, scale, latency, consistency, retention, and what is explicitly out of scope.

Design

Define APIs and data models, then connect components through the critical read and write paths.

Stress-test

Identify bottlenecks, failures, security concerns, and the trade-offs behind your scaling choices.

Self-review rubric

What a strong practice attempt includes

  • Requirements drive the architecture
  • APIs and data ownership are explicit
  • Scale and failure modes are addressed
  • Trade-offs are explained instead of hidden
Likely follow-ups

Answer the main question first, then take these on one at a time:

  • How do resumable uploads work?
  • How are conflicts resolved?
  • What changes for shared folders?
Avoid these mistakes

Check your recording or written solution against this list:

  • Ignoring offline clients
  • No conflict model
  • Treating storage as one database
Sources and methodology

This guide combines general interview-practice patterns with the public hiring material below. The practice prompt and coaching are PiriPiri AI editorial content, not official Google questions or answers.

Google Careers: how we hire ↗
Official sources reviewed 20 September 2026.