Interview prep

System design challenges

64 real design questions asked at top companies — each card names the core concept it tests and the companies that ask it, and opens a worked design with its diagram and trade-offs. Use the filters to find one, then sketch your approach and check yourself against its concept. Study material, not a timed test.

64 challenges
#13 Distributed Orchestration

Job Scheduler

Netflix Google Atlassian
#42 P2P Architecture/Resilience

Distributed Botnet

Meta Lyft

What to prepare across

The full interview surface spans ten themes. Work top to bottom — the product designs come first, the failure-mode and security hardening last.

1: High-Level Product & System Designs Questions 1-64

The strategic importance of product-centric system design lies in the candidate’s ability to move beyond technical silos and understand the "why" behind the "how." These questions test the translation of vague business requirements—often pr

2: Scenario-Based Troubleshooting & Scaling Questions 65-79

Designing for the "Happy Path" is an entry-level competency; the true test of a Senior or Staff Engineer is designing for the "Failure Path." In high-stakes environments, systems do not just slow down; they experience cascading failures. Tr

3: Core Distributed System Mechanics & Architecture Questions 80-109

The "Core Mechanics" layer represents the fundamental laws of distributed systems—the CAP Theorem, Paxos, and Consensus algorithms—that govern all higher-level designs. Ignoring these laws is the primary reason large-scale systems fail duri

4: Meta & Interview Execution Strategy Questions 110-114

The "Delivery Framework" is a strategic asset; a technical solution is only as good as the communication of its constraints. Staff-level candidates don't start drawing; they start asking.

5: Advanced Platform Architecture & Microservice Orchestration Questions 115-150

As organizations scale, the transition to microservices becomes a necessity, introducing the strategic importance of service partitioning, circuit breakers, and global load balancing.

6: API Design, Gateways, and High-Throughput Streaming Questions 151-180

API Gateways decouple internal complexity from the external world. In high-throughput environments, the choice of protocol is not stylistic—it's a performance mandate.

7: High-Throughput Data Pipelines & Real-Time Analytics Questions 181-220

The "Analytical Layer" dictates how quickly raw data becomes actionable. The choice between Lambda and Kappa architectures depends entirely on your reconciliation requirements.

8: Storage Engine Internals, Sharding & Caching Questions 221-260

The choice between B-Trees (Postgres/MySQL—read-optimized) and LSM-Trees (Cassandra/LevelDB—write-optimized) dictates the system's performance ceiling.

9: Low-Level Design LLD

LLD ensures that the code inside our "boxes" is maintainable and reusable. Mapping nouns to variables and actions to methods is the starting point.

10: Failure Modes, Edge Cases, & Security Hardening Questions 291-314

Staff Engineers design systems that are secure by default.

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