CrackingWalnuts
Today's Lineup
Pattern Pick
Heap / Top-K Pattern
DSA TemplateIntermediate
ExploreDesign Blueprint
Expression Evaluator
Low Level DesignAdvanced
ExploreScale Study
Design E-Commerce Flash Sales
System DesignHard
Deep divePacket Probe
Server-Sent Events (SSE)
Networking & ProtocolsBeginner
ExploreStaff+ Prep
Engineering Hiring & Team Building
Staff+ InterviewAdvanced
ExploreKernel Dive
POSIX Threads
Linux InternalsIntermediate
Deep dive
Explore
DSA Templates
35Algorithm patterns & code templates
System Design
39End-to-end architecture problems
Low Level Design
90Design patterns & practical code
Key Technologies
59Deep dives into core tech
Infrastructure
35Production systems & operations
Networking & Protocols
51TCP, HTTP, TLS, DNS & more
Distributed Systems
38Consensus, replication & more
Linux Internals
84Kernel, networking & system calls
Cheat Sheets
24Quick reference cards for interviews
Recent Posts
System Design: Job Scheduler (10M Jobs/day, DAG Dependencies, Effectively-Once Execution)
System Design
Apr 15, 2026 · 61 min
System Design: LeetCode (Code Sandbox, Container Isolation, Real-Time Contests)
System Design
Apr 12, 2026 · 68 min
System Design: URL Shortener (10B Short URLs, 100K Redirects/sec)
System Design
Apr 11, 2026 · 42 min
Leadership
VPTechnical Due Diligence
“Technical due diligence should evaluate architecture, team capability, and tech debt in equal measure”
Org Design
EnterpriseSecurity Team Integration
“Application Security (AppSec), Security Operations (SecOps), and Governance/Risk/Compliance (GRC) are three distinct functions that require different skill sets, tools, and team structures. Treating security as one monolithic team breaks down past 5-6 people”
530+Articles
27Interactive Tools
16Categories
6Learning Stages
Learning Path
Discover Today
Kong
Cloud-native API gateway built on NGINX
Service Discovery & Registration
Services need to find each other dynamically when IPs change constantly in containerized environments
Write-Ahead Log
Every durable database writes intentions to a sequential log before touching actual data files. If the process crashes mid-write, the log contains everything needed to either finish the operation or roll it back cleanly