System design interview structure in HLD - System Design Exercise

Design: System Design Interview Structure

Includes the interview phases, key questions to ask, and evaluation criteria. Excludes specific system design problems or technologies.

Functional Requirements

FR1: Provide a clear step-by-step approach to conduct a system design interview

FR2: Include key phases such as requirement gathering, high-level design, detailed design, and scaling discussion

FR3: Ensure the structure supports evaluating candidate's problem-solving and communication skills

FR4: Allow flexibility for different system design problems and candidate experience levels

Non-Functional Requirements

NFR1: The interview should fit within a 45-minute to 1-hour time frame

NFR2: The structure must be simple enough for interviewers and candidates to follow easily

NFR3: Focus on clarity and logical progression without overwhelming technical jargon

NFR4: Support both remote and in-person interview formats

Think Before You Design

Questions to Ask

❓ Question 1

❓ Question 2

❓ Question 3

❓ Question 4

❓ Question 5

Key Components

Requirement gathering and clarification

High-level system architecture

Component design and data modeling

Scaling and bottleneck identification

Trade-off analysis and alternatives

Design Patterns

Divide and conquer approach

Iterative refinement

Use of diagrams and sketches

Ask clarifying questions

Summarize and confirm understanding

Reference Architecture

Interview Structure
+-------------------------+
| 1. Requirement Gathering |
+-----------+-------------+
            |
            v
+-------------------------+
| 2. High-Level Design     |
+-----------+-------------+
            |
            v
+-------------------------+
| 3. Detailed Design       |
+-----------+-------------+
            |
            v
+-------------------------+
| 4. Scaling Discussion    |
+-----------+-------------+
            |
            v
+-------------------------+
| 5. Wrap-up and Feedback  |
+-------------------------+

Components

Requirement Gathering

Interview conversation

Understand what the system should do and clarify ambiguities

High-Level Design

Whiteboard or digital drawing tool

Outline main components and their interactions

Detailed Design

Diagramming and discussion

Design key components, data models, and APIs

Scaling Discussion

Verbal reasoning

Identify bottlenecks and propose scaling strategies

Wrap-up and Feedback

Conversation

Summarize design and provide candidate feedback

Request Flow

1. Interviewer presents the problem and candidate asks clarifying questions.

2. Candidate gathers and confirms requirements with interviewer.

3. Candidate sketches high-level architecture showing main components.

4. Candidate explains detailed design of critical components and data flow.

5. Candidate discusses how to scale the system and handle failures.

6. Interviewer and candidate summarize the design and discuss trade-offs.

7. Interviewer provides feedback and concludes the interview.

Database Schema

Not applicable for interview structure design.

Scaling Discussion

Bottlenecks

Candidate runs out of time before completing design

Candidate focuses too much on details too early

Interview lacks clear structure causing confusion

Candidate struggles to communicate ideas clearly

Solutions

Allocate time per phase and gently guide candidate if needed

Encourage starting with high-level design before details

Use a consistent interview framework for clarity

Encourage candidate to verbalize thought process and ask questions

Interview Tips

Time: Spend 5-10 minutes on requirement gathering, 10-15 minutes on high-level design, 15-20 minutes on detailed design and scaling discussion, and 5-10 minutes on wrap-up and feedback.

Clarify requirements before jumping into design

Start with a simple high-level architecture

Iteratively add details and justify choices

Discuss scaling and trade-offs realistically

Communicate clearly and ask clarifying questions