Advanced~4h
Reliability in System DesignInterview Readiness Check
Fault tolerance, circuit breakers, rate limiting, disaster recovery.
reliabilityfault-tolerancecircuit-breakerrate-limitingavailabilitysla
Learning path
Try a sample question
A service has an SLA of 99.9% uptime. How much total downtime is allowed per year?
A.~52 minutes
B.~8.7 hours
C.~43.8 hours
D.~3.65 days
Sign up free to take the full check and see the answer with an explanation.
What this module tests
- Conceptual understanding of reliability fundamentals
- Trade-offs and design decisions in real system scenarios
- reliability and fault-tolerance — applied knowledge
- Interview-style reasoning and explanation quality
Free to start
Take the Reliability check →
10 questions · Dimension scoring · AI coach feedback · Shareable result
Test your knowledge — free →No credit card · Takes 10–15 min
Frequently asked questions
- What does the Reliability check test?
- The check covers fault tolerance, circuit breakers, rate limiting, disaster recovery. Questions span beginner to advanced difficulty and test both conceptual understanding and practical trade-off reasoning.
- What keywords should I know for Reliability?
- Key concepts include: reliability, fault-tolerance, circuit-breaker, rate-limiting, availability, sla. These frequently appear in system design interviews at product and infrastructure companies.
- How many questions are in the check?
- Each check has 10 questions — a mix of MCQ and short-answer. You get scored by dimension (e.g., scalability, consistency) so you know exactly where to focus.
- How long does it take to study Reliability?
- Most engineers spend around 4 hours on this module. The check itself takes about 10–15 minutes. You can retake it up to 3 times per day.
- What prerequisite knowledge do I need before Reliability?
- Reliability builds on Microservices and Scalability. Complete those first for the best results.
- Is reliability, fault-tolerance, circuit-breaker covered?
- Yes. The Reliability module covers reliability, fault-tolerance, circuit-breaker among other key concepts. The check includes questions that reflect real system design interview patterns.