SYSTEM DESIGN

Stop guessing what “good” looks like.

Draw the system. Explain your tradeoffs. Get back feedback specific enough to act on. Keep grinding.

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Overall Score

Design Twitter Feed

82
Data Storage
8
API Design
7
Scalability
9
Tradeoff Reasoning
8
Communication
7

Critique

“Your caching layer handles read-heavy loads well, but the write path lacks async processing — a bottleneck at scale.”

Sophlow canvas showing a system design diagram being scored by AI — Overall Score 82, with per-dimension feedback

The Loop

Build. Explain. Get better.

01

Draw your architecture

Sketch the system on an interactive canvas — components, connections, data flows. The same way you'd do it in front of an interviewer.

02

Explain your decisions

Write why. Which database and why not the other. What breaks at 10× traffic. Where you'd cut scope under pressure.

03

Get critiqued in seconds

Scored across 7 dimensions. Specific feedback on what's missing. Follow-up questions that probe the weakest parts of your design.

Problem Set

Real problems. Real rubrics.

Hand-curated problems with a 7-dimension rubric — the same criteria a staff engineer would use in an actual interview loop. Sign in to begin.

EasyFundamentals
Design TinyURL
Design a URL shortening service that creates short aliases for long URLs and redirects users efficiently at scale.
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MediumSocial
Design Twitter
Design a social media platform focused on short-form content and real-time feed delivery to hundreds of millions of users.
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MediumMessaging
Design a Chat System (WhatsApp)
Design a real-time messaging service that delivers text and media to individuals and groups at scale, with reliable offline delivery and presence tracking.
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HardReal-Time
Design Uber
Design a ride-sharing platform that matches riders with nearby drivers in real time, tracks trips, and handles millions of concurrent location updates.
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What you get

Feedback that doesn't let you off the hook.

  • Per-dimension scores across 7 rubric criteria — not a single pass/fail.
  • Specific critique: "Your write path has no async processing" — not "consider scalability."
  • Follow-up questions that probe the weakest parts of your design — like a real interviewer would.

Your next interview loop starts here.

Pick a problem, design your architecture, and get specific feedback in seconds.

Start Practicing

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