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 Google Photos–like service
System Design: Google Photos–like Service (Web + Mobile) Context Design a large-scale consumer media service that ingests, stores, indexes, and serves...
Design ride-hailing pricing with fairness and pooling
System Design: Ride-Hailing Pricing Engine Context Design a pricing engine for a ride-hailing platform that maximizes revenue while ensuring fairness ...
Design real-time top-K products service
Question Design a real-time service that ingests a continuous stream of purchase events with the schema (customer_id, item_id, timestamp) and continuo...
Design a flight search platform
Design a large-scale flight search service similar to a consumer travel metasearch product. Users should be able to search one-way and round-trip itin...
Design a resource change tracking database
Scenario You are building part of an Azure-like cloud control plane. Resources (VMs, networks, storage accounts, etc.) are stored as JSON documents an...
Design an encrypted log collection system
Scenario Design a log collection system that gathers logs/events from services running in multiple edge data centers and delivers them to a central pl...
Trace and reduce redundant curl requests
Instrument and Optimize a Client's HTTP Requests for a Workflow You are pair-programming with the interviewer. You have a client (a script or applicat...
Design a Random Number Generation API
System Design: Random Number Service (REST + Streaming) You are designing a high-scale service that generates random numbers and exposes both REST and...
Design a scalable parking lot system
System Design: Multi-Level Parking Lot Service Context Design a production-grade parking lot system for a large, multi-level facility. The system shou...
Design a distributed key-value store
Design a Distributed Key–Value Store (Technical Screen) Context You're designing a cloud-native, multi-tenant key–value (KV) storage service for inter...
Explain Redis design, persistence, and scaling
Redis: Data Structures, Persistence, Eviction, High Availability, and Operational Pitfalls Context: You are designing a latency-critical backend that ...
Design an online real-time chess game
Design an online real-time chess service, similar to chess.com. Users should be able to sign in, use matchmaking, play real-time games, make moves wit...
Design an in-memory key-value store using maps
Design a low-level key-value store library (like an embedded storage engine) under an interview constraint: you may use only map/dictionary-like data ...
Design EV Telemetry Monitoring App
You are interviewing for a full-stack software role on an electric-vehicle team. Design an internal application that displays live vehicle telemetry, ...
Design a ticketing purchase system
System Design: High-Concurrency Ticket Purchasing With Seat Maps You are asked to design an end-to-end ticketing system for large on-sale events (e.g....
Design and explain your project architecture
Question Pick one of your recent projects and walk an interviewer through its architecture end-to-end. Sketch a high-level diagram, then go deep on th...
Explain cloud computing fundamentals
Design a Cloud-Native, Horizontally Scalable, Fault-Tolerant Web Application for Millions of Users Context You are asked to design, deploy, and operat...
Explain multithreading and locks
Multithreading, Locks, Concurrency Hazards, and a Bounded Queue Design Context: Technical screen for a software engineering role. You are asked to dem...
Design feedback and feature rollout platform
System Design: Feedback + Feature Rollout Platform Context Build a multi-tenant platform that lets product teams: - Collect end-user feedback from app...
Scale median under memory constraints
Design a Scalable Streaming Median Service Under Memory Constraints Context You are building a service that consumes a very large or unbounded stream ...