Learn to design scalable, reliable systems that handle millions of users. System design interviews test your ability to architect real-world applications, considering tradeoffs, scalability, and best practices.
Core Topics:
Scalability: Load balancing, horizontal vs vertical scaling
Storage: Databases (SQL vs NoSQL), caching (Redis, Memcached)
Reliability: Replication, failover, disaster recovery
Performance: CDNs, caching strategies, database indexing
Common Design Questions:
Design URL shortener (bit.ly)
Design rate limiter
Design Twitter/Instagram feed
Design messaging system (WhatsApp)
Design file storage (Dropbox)
Interview Level: Senior engineers (L5+) at FAANG companies. Requires 3-5+ years experience to tackle effectively.
Preparation: Study system design patterns, understand distributed systems fundamentals, and practice mock interviews.
Core Requirements A collaborative document editor allows multiple users to edit the same document simultaneously, with changes reflected in near-real-time […]
Requirements and Scale An analytics pipeline collects events from product surfaces (web, mobile, backend services), processes them in real time
Core Entities Event: event_id, name, venue_id, event_date, doors_open, start_time, status (ON_SALE, SOLD_OUT, CANCELLED, COMPLETED), total_capacity. Venue: venue_id, name, address, seating_map_url,
Core Entities Cart: cart_id, user_id (nullable for guest), session_id (for guest carts), status (ACTIVE, MERGED, ORDERED), created_at, updated_at, expires_at. CartItem:
Core Requirements A coupon system allows businesses to issue discount codes that customers apply at checkout. Types: percentage discount (20%
Core Entities Customer: customer_id, name, date_of_birth, ssn_hash, address, kyc_status (PENDING, VERIFIED, REJECTED). Account: account_id, customer_id, account_type (CHECKING, SAVINGS, MONEY_MARKET), status
Why Audit Logs? An audit log records every significant action in a system: who did what, to which resource, when,
Core Entities Rider: rider_id, name, phone, email, payment_method_id, rating, total_trips. Driver: driver_id, name, phone, license_number, vehicle_id, status (OFFLINE, AVAILABLE, ON_TRIP),
The Flash Sale Problem A flash sale offers a limited quantity of items at a steep discount for a short
Core Requirements An inventory management system tracks the quantity of products across one or more warehouses, coordinates stock reservations during
Core Entities Workspace: workspace_id, name, owner_id, plan (FREE, PRO, ENTERPRISE), created_at. Board: board_id, workspace_id, name, description, visibility (PUBLIC, PRIVATE, WORKSPACE),
Core Entities Auction: auction_id, seller_id, item_id, title, description, start_price, reserve_price (nullable, minimum price to sell), buy_now_price (nullable, instant purchase), start_time,
Core Requirements A digital wallet holds a user’s balance and enables peer-to-peer transfers. Key operations: add money (top-up from a
Why Resilience Patterns? In a microservices architecture, service A calls service B which calls service C. If C is slow
Core Entities Course: course_id, title, description, instructor_id, category, level (BEGINNER, INTERMEDIATE, ADVANCED), language, price, published_at, status (DRAFT, PUBLISHED, ARCHIVED), total_enrolled.
