Proximity Service (Find Nearby) Low-Level Design
8 min read A proximity service answers “find all restaurants / drivers / users within R km of this location” with low latency […] Read article
System Design
System Design
Ticket Booking System Low-Level Design
9 min read A ticket booking system like Ticketmaster must handle concurrent seat selection, hold expiry, payment confirmation, and flash sale traffic spikes. Read article
Algorithms, Coding Interview Questions, Dynamic Programming
Dynamic Programming on Intervals Interview Patterns
9 min read What is Interval DP? Interval DP is a dynamic programming pattern where you optimize over all sub-intervals of a range. Read article
System Design
Gaming Leaderboard System Low-Level Design
8 min read Requirements A gaming leaderboard system must support: Update a player’s score in real-time (on match completion) Query a player’s current Read article
System Design
Search Engine System Low-Level Design
8 min read Overview A search engine has four major subsystems working in a pipeline: a web crawler fetches pages from the internet, Read article
Algorithms, Coding Interview Questions, Dynamic Programming, Matrix
2D Dynamic Programming Interview Patterns
10 min read 2D DP Pattern Overview 2D dynamic programming problems use a 2D table where dp[i][j] represents the optimal value considering only Read article
System Design
Live Video Streaming System Low-Level Design
9 min read Requirements Design a live video streaming platform comparable to Twitch or YouTube Live. Key requirements: support millions of concurrent viewers Read article
System Design
Event-Driven Architecture System Design
9 min read What is Event-Driven Architecture In event-driven architecture (EDA), services communicate by publishing and consuming events rather than making direct synchronous Read article
Algorithms, Coding Interview Questions, Data Structures, Heap
Advanced Heap Interview Patterns
10 min read Advanced Heap Interview Patterns Heaps appear in a surprising number of interview problems beyond the simple “find the Kth largest Read article
System Design
Analytics Data Pipeline System Design
10 min read Analytics Data Pipeline System Design Analytics pipelines move raw events from user actions into queryable dashboards. The core challenge: volume Read article
Algorithms, Coding Interview Questions
Advanced Binary Search Interview Patterns
9 min read Advanced Binary Search Interview Patterns Binary search is not just “is target in sorted array.” The real interview value comes Read article
Algorithms, Coding Interview Questions, Depth-First Search, Graphs
Graph Traversal Interview Patterns
9 min read Graph Traversal Interview Patterns Graph problems appear in nearly every senior engineering interview. The key is recognizing which traversal fits Read article
Algorithms, Coding Interview Questions, Dynamic Programming, String Manipulation
Dynamic Programming on Strings Interview Patterns
9 min read Dynamic Programming on Strings Interview Patterns String DP problems share a common structure: a 2D table where one dimension indexes Read article
System Design
Recommendation System Low-Level Design
10 min read Recommendation System Low-Level Design Recommendation systems are one of the highest-ROI components in consumer products. They solve the discovery problem: Read article
Algorithms, Coding Interview Questions, Dynamic Programming, Tree
Dynamic Programming on Trees Interview Patterns
8 min read Core Pattern Tree DP follows a single structural pattern: post-order DFS. You recurse into children first, then compute the answer Read article