CrackingWalnuts
New
Concurrency section is live
145 topics: mental models, patterns, Go, Java, Python, real-world, performance, lock-free, debugging
Today's Lineup
Pattern Pick
Floyd-Warshall
DSA TemplateAdvanced
ExploreDesign Blueprint
Expression Evaluator
Low Level DesignAdvanced
ExploreScale Study
Design an Online Auction
System DesignHard
Deep divePacket Probe
DNS Security & DNSSEC
Networking & ProtocolsAdvanced
ExploreStaff+ Prep
Architecture Design Review
Staff+ InterviewAdvanced
ExploreKernel Dive
cgroups v2 (Control Groups)
Linux InternalsIntermediate
Deep dive
Explore
DSA Templates
44Algorithm patterns & code templates
System Design
41End-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
Concurrency
145Threads, channels, async, locks in Java + Python + Go
Distributed Systems
38Consensus, replication & more
Linux Internals
84Kernel, networking & system calls
Cheat Sheets
24Quick reference cards for interviews
Recent Posts
System Design: GitHub (200M Repos, Git Object Storage, Sparse Trigram Code Search, Per-Job VM CI)
System Design
Apr 23, 2026 · 69 min
System Design: Online Auction (50K Bids/sec, Effectively-Once Settlement, Anti-Sniping)
System Design
Apr 17, 2026 · 83 min
System Design: Job Scheduler (10M Jobs/day, DAG Dependencies, Effectively-Once Execution)
System Design
Apr 15, 2026 · 61 min
Leadership
DirectorHiring & Retaining Staff Engineers
“Staff engineer interviews must evaluate scope of influence and ambiguity tolerance, not just coding ability”
Org Design
GrowthML & AI Team Structure Patterns
“Three organizational models exist for ML teams: centralized, embedded, and hybrid. Once you get past 5 ML engineers, hybrid tends to scale best because it balances specialization with product proximity.”
530+Articles
27Interactive Tools
16Categories
6Learning Stages
Learning Path
Discover Today
TipTap
The headless rich-text editor built on ProseMirror with first-class Yjs support
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