Problem framing
Clarifies users, scale, constraints, priorities, and non-goals before selecting technology.
Live AI mock interviews available
Practice a System Design mock interview with AI
Lead a full-length conversation from requirements through deep dives. EngMock's AI interviewer listens to your reasoning, follows your architecture on the whiteboard, and evaluates the evidence you actually produced.
Evidence-based scoring rubric
Know what the interviewer is evaluating
The report separates architecture knowledge from interview execution. Each score points back to the requirements, estimates, diagram, trade-offs, and follow-up answers visible in your session.
See how interactive whiteboard feedback works →Capacity reasoning
Uses traffic, storage, latency, and availability estimates to justify the architecture.
Interfaces and data
Defines APIs, schemas, ownership boundaries, and the main read and write flows.
Scale and reliability
Finds hotspots, models partial failures, and explains recovery, observability, and degraded behavior.
Trade-off communication
Compares viable alternatives and connects each decision to the stated requirements.
Available now
Practice the complete System Design loop
Sessions combine real-time voice, a shared architecture canvas, time pressure, structured follow-ups, and a detailed post-interview report.
53 original live mock scenarios
Cover classic distributed systems, AI infrastructure, agent systems, security, reliability, and modern platform architecture.
Clarify requirements
Turn an ambiguous prompt into functional requirements, constraints, and a clear interview plan.
Estimate the workload
Quantify traffic, storage, latency, availability, and the assumptions driving your architecture.
Design the system
Define APIs, data models, components, and data flows on an interactive whiteboard.
Defend trade-offs
Respond to follow-ups on scaling, consistency, reliability, bottlenecks, and failure recovery.
Two complementary libraries
Simulate, review, and broaden your coverage
Live mock scenarios
Use the curated scenario library for timed, interactive interviews with voice, whiteboard awareness, playback, and evidence-based feedback.
Explore all live scenarios →Candidate-Reported Question Bank
Browse paraphrased System Design prompts reported by candidates. Public previews are available now; full question access is included with any EngMock credit pack.
Browse System Design reports →System Design mock interview FAQ
Practice with a clear interview standard
- What happens in an EngMock System Design mock interview?
- You clarify requirements, estimate scale, define APIs and data models, draw an architecture on the interactive whiteboard, answer adaptive follow-ups, and receive an evidence-based report tied to the work you produced.
- Can the AI interviewer understand my architecture diagram?
- Yes. The interviewer follows the candidate-authored whiteboard structure and uses the visible components and connections as context for questions about bottlenecks, consistency, reliability, and failure recovery.
- How should Senior and Staff candidates practice differently?
- Senior candidates should demonstrate complete requirements, interfaces, data flow, scale, and reliability. Staff candidates should also make organizational boundaries, migration strategy, operational risk, and long-term technical direction explicit.
Practice the complete System Design loop
Choose a System Design scenario, explain your decisions aloud, draw the architecture, and review exactly where your interview signal was strong or incomplete.
Start a System Design mock