System Design Mock
A 450-question bank of real interview topics, served as 40-question, 75-minute mocks: back-of-the-envelope estimates, storage, caching, Kafka, consensus, reliability, APIs and classic design-X problems with six case studies. Levels run from fundamentals to staff-level trade-offs, and every option comes with the reasoning behind it.
Syllabus
5 domains · 10 skills, weighted like the official blueprint.
1Foundations and Estimation15% of the exam · 2 skillsMastery—
2Data and Storage25% of the exam · 2 skillsMastery—
3Caching and Messaging20% of the exam · 2 skillsMastery—
4Distributed Systems and Reliability25% of the exam · 2 skillsMastery—
5APIs and End-to-End Designs15% of the exam · 2 skillsMastery—
Sample questions with answers
10 questions from the SYS-DES bank, with an explanation for every option. No sign-up needed.
Questions about this exam
How many questions are in a full System Design Mock, and how long is it?
40 questions in 75 minutes. Each mock draws questions from every domain in proportion to its weight, so the mix matches the blueprint.
What score do you need to pass it?
Results are reported from 0 to 100, and 70 is the passing score used in these mocks. Harder questions carry more weight.
What does the System Design Mock cover?
5 domains: Foundations and Estimation (15%), Data and Storage (25%), Caching and Messaging (20%), Distributed Systems and Reliability (25%) and APIs and End-to-End Designs (15%).
How can I practise for it?
Start with the free 15-question diagnostic to find your weak spots, drill any skill with an explanation after every answer, retry your mistakes with spaced review, then sit timed full mocks.
How is my readiness score worked out?
It weighs your recent answers on each skill by difficulty, combines the skills by their exam weight into a predicted score, and reports your chance of reaching the pass mark. How scoring works