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."
Architect serving and storage for recommender
System Design: Recommendation Service (Serving + Data Infrastructure) Context Design a production-ready recommendation service for a large-scale consu...
Design coding platform leaderboard system
System Design: Scalable Coding Platform with Live Global Leaderboard Context Design a coding challenge platform (similar to LeetCode) where users subm...
Design a game leaderboard service
Design a game scoring leaderboard system. Core requirements - Players can submit/update their score. - A player can view: 1. Their own score and ran...
Design a Real-Time Suggestions Service
System Design: Real-Time Typeahead/Autocomplete Context Design a real-time typeahead/autocomplete service for a consumer-facing web and mobile applica...
Design coding platform with global leaderboard
Scenario Design a LeetCode-like online coding practice platform that also has a global leaderboard (e.g., Top K users by score) and can show a user’s ...
Describe end-to-end design of past project
System Design Deep Dive: Past Project End-to-End Provide a detailed, end-to-end walkthrough of a significant technical project you led or contributed ...
Design async job orchestration and notification service
System Design: Batch Orchestration Over an External Asynchronous Cluster Context You are designing a backend service that accepts a list of job parame...
Design keyword search for social posts
Design a Facebook-like post search feature: - Input: one or more keywords. - Output: all (or top-K) posts that contain the keyword(s). - Assume posts ...
Design a Story feature with offline support
Design a “Story” feature (similar to a social app’s stories) with the following capabilities: Core user features - Users can create a story (photo/vid...
Design secure multi-tier cloud infrastructure
System Design: Multi-tier VPC Architecture for a Large-Scale Application You are designing and deploying a production-ready, multi-tier network on AWS...
Design a recommendation system
System Design: Large-Scale Home-Feed Recommendation System Problem Design a large-scale recommendation system for a consumer app's home feed. Describe...
Review getEvents endpoint for readability, performance, scalability, security
Question You are given a code snippet that implements an HTTP GET /events handler (getEvents). The handler queries events from a database and, for eac...
Implement auth and profile APIs
Design an In-Memory HTTP API for Auth and Profile Management Context Design a minimal, single-node, in-memory HTTP API that supports user registration...
Design key management service
Design a Key Management Service (KMS) You are asked to design a production-grade, multi-tenant Key Management Service. A client provides a key identif...
Prioritize rooms for allocation
System Design: Room Allocation and Ranking Service Context and assumptions: - The client sends a meeting request with: (a) time window or fixed start/...
Design distributed parallel job processing
Design a Distributed System for Parallel Job Execution Context You are asked to design a highly available, horizontally scalable service that executes...
Design school-to-guardian messaging with acknowledgments
System Design: Guardian Acknowledgement Messaging Platform Context Design a system that enables school staff to send messages to students' guardians, ...
Design a multithreaded CPU 1D convolution
Question Design and implement a multithreaded CPU version of the valid 1‑D convolution. Valid convolution produces an output of length M = N − K + 1, ...
Design a Collaborative Notes Service
Design a simple collaborative notes service, similar to a lightweight version of an online document editor. The system should allow users to: - Create...
Design user top-10 songs service
Design a Service to Compute Each User's Top 10 Songs Context You are designing a backend service for a large-scale music streaming platform to compute...