System Design Interview Questions
Practice 1,120 real System Design interview questions for 2026. Covers open-ended architecture problems from actual interviews with detailed solutions; System Design interview questions you can use for interview preparation at every seniority level, from mid-level backend roles to staff/infra interviews. System design rounds test how you scope problems, choose APIs and data models, size and shard storage, reason about latency, consistency, fault tolerance and operational costs, and trade off complexity vs. reliability. Companies that weight this category heavily include Meta, Google, and OpenAI, with Amazon and Rippling also asking system-style problems on many teams. Expect System Design to appear mid-to-late in an onsite loop as a 45–90 minute conversational whiteboard or collaborative doc exercise; interviewers score structure, technical depth, trade-off thinking, and communication. To prepare, practice a representative set of large-scale patterns, rehearse back-of-envelope scaling math, and run mock design interviews that force you to justify trade-offs under time pressure.

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"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 News Aggregation System (Google News-style)
Design a large-scale news aggregation service similar to Google News. The system continuously discovers and crawls news articles from tens of thousand...
Design the GPU Job Scheduler for a Text-to-Video Generation Service
This system design question evaluates a candidate's ability to design a resource-scheduling layer for scarce, expensive compute under sustained overlo...
Design a Concurrent Image Processing Service
Design a Concurrent Image Processing Service Design an image-processing service in two stages. First, support one processor safely. Then scale to mult...
Deploy a Large Model to GPU Workers
Deploy a Large Model to GPU Workers Design a system that distributes a 500 GB model artifact to a fleet of 100 to 1,000 GPU workers. External ingress ...
Design a Low-Latency Metrics and Alerting Platform
Design a Low-Latency Metrics and Alerting Platform Design a multi-tenant platform that collects host and application metrics, stores time-series data,...
Design a Real-Time Like Counter for Collaborative Tasks
Design a Real-Time Like Counter for Collaborative Tasks Design the backend and client-update flow for a collaborative task product in which signed-in ...
Design Food Reviews, Votes, and Reviewer Rewards
Design Food Reviews, Votes, and Reviewer Rewards Design a service where users can rate a food item, post a written review, and upvote or downvote anot...
Design a Thread-Safe Buffered Writer with a Background Flush Thread
This question assesses a candidate's ability to design a concurrent, thread-safe component that decouples fast in-memory writes from slower disk I/O u...
Design an LLM Request Batching System
This question evaluates a candidate's ability to design a concurrent batching layer that groups individual requests into shared GPU inference calls un...
Design Chat Deletion Semantics Under Concurrent Sends
Design Chat Deletion Semantics Under Concurrent Sends Design the backend of a chat application that supports creating threads, sending messages, readi...
Find a Distributed Mode Efficiently
Find a Distributed Mode Efficiently A large multiset is partitioned across ten workers. Find the value with the highest total frequency across all wor...
Design a Dynamically Batched Inference API
Design a Dynamically Batched Inference API Design a high-concurrency HTTP API for language-model inference. Clients submit individual requests, but GP...
Design an Amazon Locker Service
Design a Single-Station Package Locker Design the classes and core workflows for one self-service package-locker station. A delivery driver deposits a...
Design an Online Chess Service from Launch to Scale
Design an Online Chess Service from Launch to Scale Design an online chess service. Players enter matchmaking, are paired into games, exchange legal m...
Design a Payment Processing System with Exactly-Once Charging
This question evaluates a candidate's ability to design a payment system that guarantees exactly-once charging under network failures, retries, and du...
Design a User Behavior Tracking (Clickstream Analytics) System
This question asks for the design of an end-to-end user behavior tracking (clickstream analytics) system, covering event collection, transport, proces...
Design a Fault-Tolerant Video Generation Platform
Design a Fault-Tolerant Video Generation Platform Prompt Design an asynchronous video-generation platform. A user submits generation parameters, check...
Design a Geolocation Search Service
Design a geolocation search service that returns relevant places or entities near a user. `hint Hint 1 Start by stating assumptions, then work from re...
Design a Centralized Logging System
Design a Centralized Logging System Design a system that collects application logs from a large fleet of microservice instances and makes them durable...
Design a Highly Available Conversational AI Service
Design a Highly Available Conversational AI Service Design a conversational AI service that accepts a user message and streams a generated response. B...