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 a scalable calendar system
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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 speaking scenarios and auth/profile API
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Design real-time ad impression and spend tracking
Scenario You are building a backend that helps an ad server decide whether a candidate ad can be delivered (e.g., not over budget / within pacing). Th...
Design short URL service with click counting
Design a production-ready service that: 1. Creates a short URL for a given long URL (URL shortening). 2. Redirects when a user visits the short URL. 3...
Design a system to detect weapon posts
System Design: Detect weapon-related posts Design a system for a social media platform to detect and moderate posts that contain weapons. A "post" may...
Design the manual review workflow
System Design: Human-in-the-Loop Review Subsystem Context You are designing a human-in-the-loop (HITL) review subsystem for a large-scale safety platf...
Design a metrics platform without alerting
Design a metrics platform (like a simplified Prometheus/Datadog metrics product) that supports collecting, storing, querying, and visualizing metrics....
Design pickup point planning for ride-hailing
You are given a ride-hailing scenario interview question: > A passenger requests a ride from somewhere in a city. The driver is currently at a known G...
Explain Your System Architecture
System Design Interview: End-to-End Architecture Deep Dive Task Explain the end-to-end architecture of a production system you built or can credibly d...
Design in-game payment wallet system
System Design: In‑Game Currency Transfers and Analytics Context You are designing the in‑game currency subsystem for an online game. Players can trans...
Design Emergency Notification System
Design a disaster or emergency notification system for an organization such as a city government, university, or large company. The system should allo...
Design personalized news aggregation service
System Design: Personalized News Aggregation Service Design a large-scale news aggregation system similar to Google News or other news aggregator prod...
Design a cloud-based global property rental platform
System design: Cloud migration for a property rental website A property dealer runs a website that lists properties (photos, location, rent details). ...
Design an S3-like Object Store
Design a highly durable object storage service similar to Amazon S3. Users can create buckets and upload, download, list, and delete objects by key. T...
How would you scale rule evaluation?
Assume the same expense-policy rule engine must now support up to 1,000,000 active rules and efficiently evaluate batches of around 1,000 expense reco...
Design appointment scheduling data model and APIs
Scenario You are extending an existing healthcare system that already has User and Patient management APIs. - Doctors and Staff are Users. - Patients ...
Design a global notification service
System Design: Globally Distributed Notification Service Context You are designing a multi-tenant notification platform that delivers real-time and sc...
Design and evolve a reservation system
System Design: Online Reservation System You are designing a backend platform to book time-based slots for services or events (e.g., appointments, cla...
Explain Kafka architecture and reliability semantics
Kafka Architecture and End-to-End Semantics You are asked to explain Kafka's core architecture and how to design for reliability and throughput in a p...