Mock Interview: System Design

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Mock Interview: System Design

Mock Interview: System Design

Simulate a 60-minute system design interview. Design a major service (URL shortener, video platform, ride-sharing, etc.).

## What You'll Learn

• Simulate a 60-minute system design interview

## Tips

• Spend 5 min on requirements, 10 min on high-level design

• Draw architecture: clients → gateway → services → storage

• Deep-dive one component: database schema, caching, bottlenecks

Clarify Requirements

You've been asked to design a URL shortener (like bit.ly). Before proposing any architecture, list the functional requirements (what the system must do) and non-functional requirements (scale, latency, availability). Estimate the request volume: how many URLs created per day, how many redirects per second at peak?

0 / 150 characters(150 more required)

High-Level Architecture

Sketch the major components of your system and explain how a write request (create short URL) and a read request (redirect) flow through it. Name each service, storage layer, and network component. Justify why you separated concerns the way you did.

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Data Model

Define the core schema or data model. What does a URL record look like? How do you generate and guarantee uniqueness of short codes? Walk through the write path at the storage level — what exactly gets stored, in what order, with what indexes?

0 / 150 characters(150 more required)

Identify Bottlenecks

Where will your system break under load? Name at least three concrete bottlenecks — in the write path, the read path, and storage — and explain what failure mode each produces at scale.

0 / 150 characters(150 more required)

Trade-offs & Alternatives

For at least two of your design decisions, explain the alternative you rejected and why you chose your approach over it. Good system design answers demonstrate awareness that every choice has a cost.

0 / 150 characters(150 more required)

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