System Design Interview Questions
Practice 981 real System Design interview questions for 2026 — System Design interview questions drawn from actual interviews with detailed solutions to power focused interview preparation. Coverage spans big tech patterns and company-specific flavors from Meta, Amazon, OpenAI, DoorDash, and Google, emphasizing software-engineering fundamentals: high-level architecture, APIs, data models, scaling strategies, and component-level tradeoffs you’ll need to codify on a whiteboard or virtual diagram tool. What’s distinctive in 2026: interviewers evaluate your ability to reason about capacity, latency, consistency, fault tolerance, and operational ownership while making measurable tradeoffs; expect more questions about AI/LLM inference pipelines, vector search and feature stores alongside classic problems like caching, sharding, messaging, and geo-distribution. Prepare by practicing clear HLD-to-LLD transitions, writing concise API contracts, doing back-of-envelope capacity math, and running timed mock interviews that force diagram clarity and follow-up handling. Focus on metrics, failure modes, and deployment/monitoring choices — those separate good answers from great ones.
"I got asked a hardcore MCM DP question and I saw it on PracHub as well. Solved that question in 5 minutes. Without PracHub I doubt I could solve it in 5 hours. Though somehow didn't get hired, perhaps I guess I solved it too fast? /s"
"Believe me i'm a student here jn US. Recently interviewed for MSFT. They asked me exact question from PracHub. I saw it the night before and ignored it cause why waste time on random sites. I legit wanna go back and redo this whole thing if I had chance. Not saying will work for everyone but there is certainly some merit to that website. And i'm gonna use it in future prep from now on like lc tagged"
"10 years of experience but never worked at a top company. PracHub's senior-level questions helped me break into FAANG at 35. Age is just a number."
"I was skeptical about the 'real questions' claim, so I put it to the test. I searched for the exact question I got grilled on at my last Meta onsite... and it was right there. Word for word."
"Got a Google recruiter call on Monday, interview on Friday. Crammed PracHub for 4 days. Passed every round. This platform is a miracle worker."
"I've used LC, Glassdoor, and random Discords. Nothing comes close to the accuracy here. The questions are actually current — that's what got me. Felt like I had a cheat sheet during the interview."
"The solution quality is insane. It covers approach, edge cases, time complexity, follow-ups. Nothing else comes close."
"Legit the only resource you need. TC went from 180k -> 350k. Just memorize the top 50 for your target company and you're golden."
"PracHub Premium for one month cost me the price of two coffees a week. It landed me a $280K+ starting offer."
"Literally just signed a $600k offer. I only had 2 weeks to prep, so I focused entirely on the company-tagged lists here. If you're targeting L5+, don't overthink it."
"Coaches and bootcamp prep courses cost around $200-300 but PracHub Premium is actually less than a Netflix subscription. And it landed me a $178K offer."
"I honestly don't know how you guys gather so many real interview questions. It's almost scary. I walked into my Amazon loop and recognized 3 out of 4 problems from your database."
"Discovered PracHub 10 days before my interview. By day 5, I stopped being nervous. By interview day, I was actually excited to show what I knew."
"I recently cleared Uber interviews (strong hire in the design round) and all the questions were present in prachub."
"The search is what sold me. I typed in a really niche DP problem I got asked last year and it actually came up, full breakdown and everything. These guys are clearly updating it constantly."
Design ticketing system with seat hold
Design an online ticketing system (similar to Ticketmaster) that allows users to browse events, select seats, and place a temporary 5-minute hold on s...
Design UberPool matching with zero Manhattan detour
Design a ride-sharing (UberPool-like) system focused on matching and routing. You are operating on a grid where travel distance is Manhattan distance:...
Design a Therapy Matching Marketplace
Design the backend for a marketplace that matches patients with therapists. The platform should support: - Patients searching for therapists by specia...
Design an ad frequency capping system
System Design: Ads Frequency Capping You are designing an ad-serving platform (e.g., for a streaming service with ads). The product requires frequency...
Design a prioritized log manager with eviction
Design a Log Store with Priority- and Recency-Aware Eviction Context You are designing an in-memory (or on-disk) log storage component. Each inserted ...
Design an Instagram-like auction platform
Design an Instagram-like platform that supports auction posts. Users can: - Create an auction post with photos/video, description, category/tags. - Se...
Design a Scalable Like Counter
Design a large-scale service that stores and serves like counts for content items. Requirements: - Users can like and unlike an item. - Product pages ...
Design OOD for probabilistic Minesweeper
Object-Oriented Design: Minesweeper with Per-Cell Mine Probabilities Context Design an object-oriented Minesweeper game. The board is a grid of cells....
Design a Pipeline to Process a Billion Clickstream Events Per Day
You are designing the data infrastructure for a large consumer web/mobile product. The product emits a clickstream: every page view, tap, scroll, and ...
Design a scalable metrics monitoring system
Design a Metrics Monitoring System for Large-Scale Services Context You are designing a metrics monitoring system for large-scale, cloud-native micros...
Design a scalable key-value configuration service
Design a Globally Distributed Key–Value Configuration Service Background You are asked to design a globally distributed key–value configuration servic...
Design an online coding judge
Question Design an online coding practice and judging platform (think LeetCode / HackerRank / Codeforces) where users submit solutions that are compil...
Design a company-wide monitoring system
You are asked to design a monitoring system used company-wide. Goals - Collect and query telemetry for many services/hosts - Support alerting and dash...
Explain shader compilers and graphics APIs
Shader Compilation Pipeline, API Comparison, and Minimal Compiler Design Context Assume you are targeting modern discrete GPUs and common programmable...
Schedule and execute future payments
System Design: Scheduled Payments Execution Context You are building a balance-transfer service (e.g., an internal wallet). Users can schedule a payme...
Design speaking scenarios and auth/profile API
System Design Task: Speaking-Scenario Practice Feature + MVP Auth API Context: You are designing a new speaking-scenario practice capability for a lan...
Implement FastAPI CRUD endpoints from skeletons
Implement Update and Delete Endpoints in a FastAPI CRUD Service Context You are given a FastAPI project that already has working Create and Read endpo...
Design line-preserving file chunker pipeline
System Design: Pack Text Lines into Exact 100 MB Output Files Design a data pipeline that reads many text files of varying sizes and emits output file...
Design donation database and failure handling
System Design: Donations Platform with One-Time and Recurring Payments Context Design a backend for a donations platform that supports campaigns, one-...
Design a scalable calendar system
System Design: Multi-Tenant Calendar at Massive Scale You are designing a multi-tenant calendar platform used by hundreds of millions of users across ...