# How to practice system design interviews > You can practice system design interviews in five ways: books, courses, peers, human mock interviews and AI mock interviewers. Most engineers combine two or three ways. Books and courses teach the concepts. Only a live round, with a person or an AI, trains you to think and talk at the same time. Source: https://sysround.com/guides/how-to-practice-system-design-interviews Updated: 2026-11-05 ## The five ways to practice Each way trains a different skill. Reading trains your knowledge. A live round trains your structure, your speed and your explanations under questions. A good plan uses both. - Books and written guides: the concepts and worked examples, at your own speed. - Video and text courses: a structured path through the common questions. - Practice with peers: free live rounds, if you have a partner. - Human mock interviews: feedback from an experienced interviewer, for a fee. - AI mock interviewers: a full live round at any time, with feedback at the end. ## Books and written guides Two books are common starting points. System Design Interview by Alex Xu walks through classic questions step by step. Designing Data-Intensive Applications by Martin Kleppmann explains how databases, replication and streams work in depth. Books are the best way to learn the building blocks. They do not train the conversation. You cannot practice how to answer follow-up questions from a book. ## Video and text courses Several platforms teach system design for interviews, for example ByteByteGo, Hello Interview, Educative and Exponent. They give you lessons, diagrams and model answers for the common questions. Courses give you a clear path, but most of the work is passive. Watch a lesson, then practice the same question out loud before you look at the answer. ## Practice with peers Take turns as the interviewer and the candidate. Use a timer and a shared whiteboard. A peer round is free and it is a real conversation. The weak points are the schedule and the bar. Your partner must be free at the same time. A peer who does not interview candidates often may not know the bar for your level. ## Human mock interviews Paid services, for example interviewing.io and Hello Interview, connect you with engineers who interview candidates at large companies. A good human interviewer gives you the most realistic feedback. Each session costs money and needs a booking. Most engineers book one or two human mocks in the last weeks before an important onsite. ## AI mock interviewers An AI mock interviewer does a full round with you when you want. SysRound is one example. Its interviewer, Alex, talks with you or types with you. Alex asks about requirements and numbers, reads your whiteboard and asks follow-up questions on the hard parts. At the end, you get a score for each of seven skills and a model answer. AI rounds are good for frequent practice: you can do a round every day at low cost. The AI can be wrong, so use the feedback as one data point. Before an important onsite, also do at least one round with a person. ## A plan that combines them This plan works for most engineers who have four to six weeks before an onsite. - Weeks 1 and 2: read the core concepts and do one question each day, slowly, with notes. - Weeks 2 to 4: do three or four timed rounds each week, with a peer or an AI interviewer. - Week 4 and later: book one or two human mock interviews. Fix the weakest skill from your feedback. - In the last week: do short daily rounds to keep your speed. Do not start new topics. ## How to choose Choose by your time, your budget and your weakest skill. - No budget: books, peers and a free AI round each day. - Onsite in two weeks: daily timed rounds and one human mock interview. - New to system design: a book or a course first, then live rounds. - Strong on concepts but nervous in interviews: many live rounds, with a person or an AI. ## Questions to practice - [Design a URL shortener like Bitly](https://sysround.com/questions/design-url-shortener): A classic first question to learn the shape of a round. - [Design a news feed like Facebook](https://sysround.com/questions/design-news-feed): A common question that tests fan-out, caching and hot keys. - [Design a distributed rate limiter](https://sysround.com/questions/design-rate-limiter): A short question to practice depth on one component. ## FAQ ### What is the best way to practice system design interviews? Combine reading with live rounds. Learn the concepts from a book or a course. Then do timed rounds out loud, with a peer, a human mock interviewer or an AI mock interviewer. The live rounds train the skill that the interview tests. ### Is there an AI mock interviewer for system design interviews? Yes. SysRound is an AI mock interviewer for system design rounds at mid, senior and staff level. You talk or type with the AI interviewer and draw on a shared whiteboard. At the end, you get feedback on seven skills and a model answer. ### Are AI mock interviews as good as human mock interviews? They are good for different things. AI rounds are available at any time and cost little, so you can practice often. A human interviewer gives more reliable feedback on a single round. Most engineers use AI rounds for frequent practice and book one or two human mocks before the onsite. ### How many mock interviews should I do before a system design onsite? Most engineers do eight to fifteen full rounds. Do them over several weeks, not in the last days. Look at the patterns in your feedback, and practice your weakest skill. ## Related concepts - [Back-of-the-envelope estimation](https://sysround.com/concepts/back-of-the-envelope-estimation) - [Caching strategies](https://sysround.com/concepts/caching-strategies) - [Database sharding](https://sysround.com/concepts/database-sharding) --- SysRound (https://sysround.com) is an AI practice tool for system design interviews. It has a voice or typed AI interviewer and a shared whiteboard. At the end, you get feedback on each skill and a model answer. The AI feedback can be wrong.