What does the system design mock interview cover?

Both HLD and LLD. HLD problems walk you through requirements clarification, capacity estimation, API design, high-level architecture, database choice, caching, scaling, and trade-offs. LLD problems walk through entity modelling, class diagrams, code implementation, edge cases, and extensibility.

Can I draw a diagram during the interview?

Yes - the session has a freeform Architecture Canvas where you can drag in load balancers, caches, queues, and microservices and connect them with arrows. The AI evaluator sees both your written answer and the diagram you sketched.

How are the answers scored?

Each step gets a rubric-based score (problem solving 30%, technical design 30%, trade-off analysis 20%, communication 20%) plus a written critique that names what you did well and what was missing. There's also a model answer to compare against.

How long does a session take?

A focused HLD problem is 45–60 minutes; LLD problems are 30–45. You can pause mid-session - your progress saves.

System Design Interview Portal

Master System Design Interviews

Practice HLD and LLD with AI-generated questions tailored to your level. Get structured, step-by-step feedback from Claude on every section - just like a real interview.

One complete mock interview - the questions a good candidate asks, the design on the canvas, and the graded review.

Interview Topics

HLD & LLD

Modes

30–60 min

Per Session

Your Sessions

How It Works

Four steps to an authentic system design interview experience

Choose your setup

Select HLD or LLD mode, pick a difficulty level (Junior / Senior / Staff), and the topic you want to practice. The AI generates a unique question every time.

AI generates question

Claude crafts a tailored, realistic system design question in seconds - complete with requirements, constraints, and an expected outcome rubric.

Work through each step

Navigate structured steps: requirements, entities, API design, architecture, database, deep dives. Each step has guided forms, the freeform Architecture Canvas for sketching the diagram, and an AI chat assistant.

Get per-step AI feedback

Submit each step and get an instant score, strengths, gaps, and a model answer from Claude. Submit all steps to see your complete interview result.

What to Expect in Your Mock Interview

A walk-through of the interview session experience

API Design Step

Design a URL Shortener - define the REST endpoints for creating, resolving, and deleting short URLs. Include authentication and rate-limiting considerations.

POST/api/urlsCreate short URL

GET/api/urls/:shortIdResolve & redirect

DELETE/api/urls/:shortIdDelete URL

✦ Evaluate Step

Skip →

AI Chat

AI Evaluation Result (after submitting a step)

82/ 100

✓ RESTful design✓ Auth considered⚠ Missing pagination

Good overall structure. Consider adding pagination parameters to the list endpoint and specifying response schemas more explicitly.

What You Get After Each Interview

Submit your interview to unlock a detailed performance report

Overall Score

Aggregated score out of 100 across all evaluated steps - see exactly where you stand.

Per-Step Breakdown

Individual scores, strengths, and gaps for every step you submitted.

Model Answers

Claude's expert reference solution for each step - including skipped ones.

Improvement Tips

Actionable feedback on what to focus on before your next interview.

What's Included

AI-Generated Questions

Unique questions every session - never the same interview twice.

3 Difficulty Levels

Junior (30 min), Senior (45 min), Staff (60 min) with distinct rubrics.

HLD & LLD Both

Practice distributed systems or OOP design in one place.

Architecture Canvas Built In

Freeform drag-and-drop whiteboard inside every HLD session - draw the diagram, don't just describe it.

Per-Step Evaluation

AI scores each section independently with strengths & gaps.

Model Answers

See expert reference solutions for every step after submission.

Progress Tracking

History, scores, and improvement trends in your dashboard.

Two Interview Tracks

Choose HLD for distributed systems or LLD for object-oriented design

High-Level Design

HLD

Steps

Requirements

Capacity Estimation

API Design

High-Level Design

Database Design

Deep Dive: Caching

Deep Dive: Scaling

Bottlenecks & Trade-offs

Sample Topics

URL ShortenerTwitter / XRate LimiterYouTubeUberChat AppDistributed Cache+ more

Low-Level Design

LLD

Steps

Requirements

Core Entities

Classes & Relationships

Code Implementation

Edge Cases & Tests

Extensibility & Trade-offs

Sample Topics

Parking LotChess GameATM MachineElevator SystemHotel BookingVending MachineLibrary+ more

Difficulty Levels

Junior

30 min

Core concepts, basic architecture, guided evaluation with relaxed scoring.

Senior

45 min

Depth, scalability, trade-offs, design patterns, and non-functional requirements.

Staff / Principal

60 min

Strict rubric, deep-dive technical questions, cost & operational excellence expected.