A system design judge should help you see where your explanation holds up and where it needs work. InterviewReady's AI interviewer gives you a system design problem, lets you draw your architecture and asks you to explain your decisions. After the round, you receive a scored report to review.
Start a free AI system design mock interview. Sign in to start your round.
How to practise
- Open the mock interview setup and choose System design.
- Set the company, role and experience level for the round.
- Review your choices and start the interview.
- Clarify requirements, draw the design and discuss the tradeoffs with the AI interviewer.
- Finish the round and read the scored report. Use the feedback to choose what to practise next.
The system design round is 45 minutes. The setup also offers a 30-minute behavioural round.
What to explain to the interviewer
Start with the product requirements and the expected load. Show how the API and data model support one important user action. Then follow that action through your architecture.
When you add a component, explain the problem it solves. A cache needs an invalidation rule. A queue needs a retry policy. A replicated database needs a decision about which copy a read can use. Discussing these details gives the interviewer something concrete to question.
If a follow-up exposes a weakness, work through it. Revising a design and explaining the consequence is useful practice for the real interview.
How to use the report
Read the report alongside the decisions you made during the round. Choose one gap to work on, revisit the relevant explanation and practise applying it to another problem. A score is feedback on that simulated round; it does not guarantee an outcome in a company's interview.
Questions to practise before the round
Work through these system design interview questions and answer outlines. They cover chat, social feeds, ride matching, rate limiting, email, dating applications, video and inventory.
For structured study, start with System Design for Interviews. The Advanced System Design course goes deeper into databases, distributed systems and research papers.
Is the system design judge free?
The AI mock interviewer is free for signed-in users. You can open the setup before signing in; starting an interview requires an account.