Media Upload Service Low-Level Design
5 min read What is a Media Upload Service? A media upload service handles ingest, validation, processing, and storage of user-generated files: profile […] Read article
System Design
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System Design
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.
System Design
Inventory Management System Low-Level Design
6 min read Requirements Track stock levels across multiple warehouses for millions of SKUs Reserve inventory when an order is placed; deduct when Read article
System Design
Order Fulfillment System Low-Level Design
7 min read What is Order Fulfillment? Order fulfillment covers the steps from a confirmed order to the item delivered to the customer: Read article
System Design
Search Indexing System Low-Level Design
6 min read What is a Search Index? A search index enables fast full-text queries over large datasets. Without an index, searching 1 Read article
System Design
Referral System Low-Level Design
7 min read Requirements Users share a unique referral code or link to invite new users Referrer earns a reward when a referred Read article
System Design
Chat System Low-Level Design (WhatsApp / Messenger)
7 min read Requirements One-on-one and group messaging (up to 500 members) Message delivery with read receipts (sent, delivered, read) Message history persistence Read article
System Design
DNS Resolver and DNS System Design
7 min read What Does a DNS Resolver Do? The Domain Name System (DNS) translates human-readable domain names (www.example.com) into IP addresses (93.184.216.34). Read article
System Design
Feature Store System Low-Level Design
7 min read What is a Feature Store? A feature store is a centralized repository for ML features. It solves the “feature engineering Read article
System Design
Dead Letter Queue (DLQ) System Low-Level Design
7 min read What is a Dead Letter Queue? A Dead Letter Queue (DLQ) holds messages that could not be processed successfully after Read article
System Design
Loyalty Program System Low-Level Design
6 min read Requirements Earn points on purchases and specific actions (sign-up, referral, review) Redeem points for discounts, rewards, or free items Tiered Read article
System Design
Event Sourcing System Low-Level Design
7 min read What is Event Sourcing? In a traditional system, the database stores the current state: “Account balance = $500.” In event Read article
System Design
Session Management System Low-Level Design
6 min read What is Session Management? Session management maintains the authenticated state of a user across multiple HTTP requests. HTTP is stateless Read article
System Design
Comment System Low-Level Design
7 min read Requirements Users can post comments on content items (posts, videos, products) Threaded replies (nested comments) up to N levels deep Read article
System Design
Cache System Low-Level Design (LRU, Write Policies, Redis Cluster)
7 min read Why Caching? A cache stores copies of frequently-accessed data in fast storage (RAM) to avoid expensive re-computation or round trips Read article
System Design
Email Delivery System Low-Level Design
7 min read Requirements Send transactional emails (password reset, order confirmation, notifications) and marketing emails (campaigns, newsletters) 100M emails/day, peak 10K/second during campaigns Read article