[{"data":1,"prerenderedAt":343},["ShallowReactive",2],{"blog-\u002Fblog\u002Fen\u002Fsystem-design-prep":3,"blog-sibling-\u002Fblog\u002Fzh-cn\u002Fsystem-design-prep":273,"related-en":275},{"id":4,"title":5,"author":6,"body":7,"cover":256,"date":257,"description":258,"draft":259,"extension":260,"faqCategory":261,"meta":262,"navigation":263,"outro":261,"path":264,"readingTime":249,"seo":265,"stem":266,"steps":267,"tags":268,"updated":261,"wordCount":271,"__hash__":272},"blog\u002Fblog\u002Fen\u002Fsystem-design-prep\u002Findex.md","How to Prepare for System Design Interviews: A Reusable Framework","Kuaimian Team",{"type":8,"value":9,"toc":242},"minimark",[10,19,24,29,32,55,58,62,65,118,121,125,137,141,144,176,179,183,190,194,226,230,239],[11,12,13,14,18],"p",{},"The scariest thing about system design interviews is that they \"have no standard answer\"—the prompt is often a single line: \"Design a URL shortener,\" \"Design a social feed.\" But open-ended doesn't mean structureless. What truly separates candidates isn't who remembers the most, but who can take a vague problem in 45 minutes and break it apart, make trade-offs, and reason it through ",[15,16,17],"em",{},"with structure",". The framework below can be applied directly to almost any system design question.",[20,21,23],"h2",{"id":22},"a-five-step-framework","A Five-Step Framework",[25,26,28],"h3",{"id":27},"step-1-clarify-requirements-5-minutes-dont-skip","Step 1: Clarify requirements (5 minutes, don't skip)",[11,30,31],{},"Jumping straight to drawing an architecture is the biggest trap for beginners. Spend a few minutes making the prompt concrete first:",[33,34,35,43,49],"ul",{},[36,37,38,42],"li",{},[39,40,41],"strong",{},"Functional requirements",": What are the core features? Which are MVP, and which can be deferred?",[36,44,45,48],{},[39,46,47],{},"Non-functional requirements",": Read-heavy or write-heavy? Do you need strong consistency? Latency targets?",[36,50,51,54],{},[39,52,53],{},"Scale",": How many daily active users? What QPS magnitude? How long is data retained?",[11,56,57],{},"Pinning down the scope aligns expectations and also shows the interviewer your product sense.",[25,59,61],{"id":60},"step-2-capacity-estimation-5-minutes","Step 2: Capacity estimation (5 minutes)",[11,63,64],{},"Use rough numbers to work out the system's magnitude—it directly drives your later technology choices. Just memorize a few common baselines:",[66,67,68,82],"table",{},[69,70,71],"thead",{},[72,73,74,79],"tr",{},[75,76,78],"th",{"align":77},"left","Quantity",[75,80,81],{"align":77},"Order of magnitude",[83,84,85,94,102,110],"tbody",{},[72,86,87,91],{},[88,89,90],"td",{"align":77},"Seconds in a day",[88,92,93],{"align":77},"≈ 86,400 ≈ 10⁵",[72,95,96,99],{},[88,97,98],{"align":77},"One text record",[88,100,101],{"align":77},"~ 100 B ~ 1 KB",[72,103,104,107],{},[88,105,106],{"align":77},"Single-machine QPS (cache hit)",[88,108,109],{"align":77},"~ tens of thousands",[72,111,112,115],{},[88,113,114],{"align":77},"Single-machine storage",[88,116,117],{"align":77},"~ TB scale",[11,119,120],{},"For example, \"100M DAU, 1 write per person\" ≈ 100M writes\u002Fday ≈ 1,000 write QPS; at a 100:1 read ratio that's 100,000 read QPS—and right away you know you must add caching and read-write splitting.",[25,122,124],{"id":123},"step-3-define-the-api-and-data-model-5-minutes","Step 3: Define the API and data model (5 minutes)",[11,126,127,128,132,133,136],{},"List the core endpoints (",[129,130,131],"code",{},"POST \u002Fshorten",", ",[129,134,135],{},"GET \u002F{code}",") and the main table\u002Fcollection fields. This step grounds the abstract problem and sets up the storage choices for the next step.",[25,138,140],{"id":139},"step-4-draw-the-high-level-architecture-15-minutes-the-core","Step 4: Draw the high-level architecture (15 minutes, the core)",[11,142,143],{},"Start from the simplest \"client → load balancer → service → database,\" then add components step by step to solve specific bottlenecks:",[33,145,146,152,158,164,170],{},[36,147,148,151],{},[39,149,150],{},"Cache"," (Redis): absorb reads, lower latency; watch out for cache penetration \u002F avalanche \u002F consistency",[36,153,154,157],{},[39,155,156],{},"Message queue"," (Kafka): shave peaks, decouple, make writes asynchronous",[36,159,160,163],{},[39,161,162],{},"Sharding \u002F read-write splitting",": how to split when a single database can't keep up",[36,165,166,169],{},[39,167,168],{},"CDN \u002F object storage",": static assets and large files",[36,171,172,175],{},[39,173,174],{},"Consistent hashing",": balancing across shard or cache nodes",[11,177,178],{},"Every time you add a component, make clear \"which specific problem it solves,\" rather than piling up buzzwords.",[25,180,182],{"id":181},"step-5-deep-dive-and-trade-offs-10-minutes","Step 5: Deep dive and trade-offs (10 minutes)",[11,184,185,186,189],{},"The interviewer will usually pick one point to probe deeply. Proactively show your sense of trade-offs: SQL vs. NoSQL, strong vs. eventual consistency, push vs. pull (the classic feed dilemma). There's no silver bullet; what matters is explaining ",[15,187,188],{},"why this choice for this scenario",".",[20,191,193],{"id":192},"quick-reference-common-topics","Quick Reference: Common Topics",[33,195,196,202,208,214,220],{},[36,197,198,201],{},[39,199,200],{},"URL shortener \u002F ID generator",": hash vs. auto-increment, Base62 encoding, collision handling",[36,203,204,207],{},[39,205,206],{},"Feeds",": push (fan-out on write) vs. pull (fan-out on read) vs. hybrid",[36,209,210,213],{},[39,211,212],{},"Rate limiting",": token bucket \u002F leaky bucket \u002F sliding window",[36,215,216,219],{},[39,217,218],{},"Unique IDs",": Snowflake, segment-based allocation",[36,221,222,225],{},[39,223,224],{},"Flash sales \u002F high-concurrency writes",": inventory pre-deduction, queue peak-shaving, oversell prevention",[20,227,229],{"id":228},"drill-the-framework-into-muscle-memory","Drill the Framework Into Muscle Memory",[11,231,232,233,238],{},"The hard part of system design is \"organizing on the spot,\" and that only comes from speaking it out loud. Pick a few classic questions and run through them against the five steps above, on a timer. Practicing alone makes it easy to feel falsely good about yourself—drop the question into Kuaimian's ",[234,235,237],"a",{"href":236},"\u002Fen\u002Fdocs\u002Fmock-interview-start","AI Mock Interview",", let the AI play the interviewer and probe at the key moments (\"why not strong consistency,\" \"what if the cache goes down\"), and you get much closer to real pressure—plus a piece of structured feedback afterward that tells you which step you missed.",[11,240,241],{},"Remember: a system design interview isn't testing how many architectures you've memorized—it's testing whether you can make reasonable trade-offs, with structure, amid uncertainty.",{"title":243,"searchDepth":244,"depth":244,"links":245},"",2,[246,254,255],{"id":22,"depth":244,"text":23,"children":247},[248,250,251,252,253],{"id":27,"depth":249,"text":28},3,{"id":60,"depth":249,"text":61},{"id":123,"depth":249,"text":124},{"id":139,"depth":249,"text":140},{"id":181,"depth":249,"text":182},{"id":192,"depth":244,"text":193},{"id":228,"depth":244,"text":229},"\u002Fcontent\u002Fblog\u002Fen\u002Fsystem-design-prep\u002Fcover.webp","2026-06-16","System design interviews have no standard answer, but they do have a standard approach. A framework that runs from clarifying requirements to capacity estimation to core components and scalability—plus a checklist of common topics—to help you make sense of those 45 minutes.",false,"md",null,{},true,"\u002Fblog\u002Fen\u002Fsystem-design-prep",{"title":5,"description":258},"blog\u002Fen\u002Fsystem-design-prep\u002Findex",[],[269,270,237],"Interview Tips","Job Search",667,"DY8cYZaBAG0KcnqHymw-vjaqp1urcxUVee3PLnwMVBo",{"path":274},"\u002Fblog\u002Fzh-cn\u002Fsystem-design-prep",[276,285,292,300,307,314,321,323,329,336],{"path":277,"title":278,"description":279,"cover":280,"tags":281,"date":284},"\u002Fblog\u002Fen\u002Fhow-to-optimize-resume","How to Build a Resume That Matches Your Target Role with Kuaimian","从零到导出，跟着这四步走一遍，你就能得到一份针对目标岗位优化过的简历。","\u002Fimages\u002Fproducts\u002Fresume\u002Feditor.webp",[282,283],"Resume Optimization","Tutorial","2026-06-23",{"path":286,"title":287,"description":288,"cover":289,"tags":290,"date":291},"\u002Fblog\u002Fen\u002Fhow-to-mock-interview","How to Run a Realistic Mock Interview Before the Real One with Kuaimian","选岗、开场、对话、复盘——跟着这三步走一遍，你就完成了一场带逐题复盘的模拟面试。","\u002Fimages\u002Fproducts\u002Fmock-interview\u002Fsetup.webp",[237,269,283],"2026-06-22",{"path":293,"title":294,"description":295,"cover":296,"tags":297,"date":299},"\u002Fblog\u002Fen\u002Fhow-to-interview-copilot","How to Get Real-Time Interview Assistance in a Live Interview with Kuaimian","下载客户端、选岗、挂起悬浮窗——跟着这三步，真面试时 AI 就坐在你身边。","\u002Fimages\u002Fproducts\u002Finterview-copilot\u002Fassist.webp",[298,269,283],"Interview Copilot","2026-06-21",{"path":301,"title":302,"description":303,"cover":304,"tags":305,"date":306},"\u002Fblog\u002Fen\u002Face-ai-interview","Ace Your Technical Interview with AI Interview Copilot","Real-time screen sharing, system audio capture, and an edge-docked teleprompter — how Kuaimian helps you perform under pressure.","\u002Fcontent\u002Fblog\u002Fen\u002Face-ai-interview\u002Fcover.webp",[269,298,270],"2026-06-20",{"path":308,"title":309,"description":310,"cover":311,"tags":312,"date":313},"\u002Fblog\u002Fen\u002Fhow-to-coding-copilot","How to Crack the Coding Questions You're Stuck On in Online Tests with Kuaimian","截屏、看思路与代码、对照作答——跟着这三步，难题也能稳过数据量。","\u002Fimages\u002Fproducts\u002Fcoding-copilot\u002Fassist.webp",[298,283],"2026-06-19",{"path":315,"title":316,"description":317,"cover":318,"tags":319,"date":320},"\u002Fblog\u002Fen\u002Fstar-method-behavioral","The STAR Method for Behavioral Interviews: Turn Your Experience Into a Persuasive Story","When the interviewer says \"Tell me about a time you resolved a conflict,\" don't ramble. Use the STAR method to break your experience into Situation, Task, Action, and Result, so every answer has structure, numbers, and impact.","\u002Fcontent\u002Fblog\u002Fen\u002Fstar-method-behavioral\u002Fcover.webp",[269,270,237],"2026-06-18",{"path":264,"title":5,"description":258,"cover":256,"tags":322,"date":257},[269,270,237],{"path":324,"title":325,"description":326,"cover":280,"tags":327,"date":328},"\u002Fblog\u002Fen\u002Fresume-ats-keywords","Beat the ATS: A Practical Checklist for Keywords and Formatting","Many resumes get filtered out by the ATS (applicant tracking system) before a human ever sees them. A practical checklist on keyword matching, formatting pitfalls, and file choices to help your resume clear the machine first.",[282,270],"2026-06-14",{"path":330,"title":331,"description":332,"cover":333,"tags":334,"date":335},"\u002Fblog\u002Fen\u002Fremote-interview-setup","The Equipment and Environment Checklist for Remote Video Interviews (Plus How to Run Your Interview Copilot Reliably)","Choppy network, muffled audio, dim lighting, messy background—remote interviews often go sideways not because you lack skill, but because your gear and environment weren't ready. A pre-call checklist for equipment, network, and environment.","\u002Fcontent\u002Fblog\u002Fen\u002Fremote-interview-setup\u002Fcover.webp",[269,298,270],"2026-06-12",{"path":337,"title":338,"description":339,"cover":340,"tags":341,"date":342},"\u002Fblog\u002Fen\u002Fsalary-negotiation","How to Negotiate Salary After Getting an Offer: Timing, Scripts, and Your Bottom Line","Negotiating isn't greedy—it's about getting paid for the value you've proven. From when to bring it up, to how to name a number, to handling \"our budget is limited,\" to holding your line: a negotiation rhythm that earns more without damaging the relationship.","\u002Fcontent\u002Fblog\u002Fen\u002Fsalary-negotiation\u002Fcover.webp",[270],"2026-06-10",1783848901341]