CrackingWalnuts
Today's Lineup
Pattern PickDSA TemplateIntermediate
Cycle Detection (Graph)
DSA TemplateIntermediate
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Design BlueprintLow Level DesignIntermediate
Game World (Tile Engine)
Low Level DesignIntermediate
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Scale StudySystem DesignHard
Design a Multi-Tenant SaaS Platform
System DesignHard
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Packet ProbeNetworking & ProtocolsAdvanced
Network Observability
Networking & ProtocolsAdvanced
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DSA Templates
35Algorithm patterns & code templates
System Design
39End-to-end architecture problems
Low Level Design
67Design 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: Ad Click Aggregator (10B Clicks/day, Lambda Architecture, Fraud Detection)
System DesignData Engineering
Apr 10, 2026 · 70 min
System Design: Ad Exchange (Real-Time Bidding, Sub-100ms Auctions, DSP/SSP, Impression Serving)
System Design
Apr 10, 2026 · 59 min
System Design: E-Commerce Flash Sales (10M Users, Coupon System, One-Per-User Enforcement)
System Design
Apr 5, 2026 · 106 min
Leadership
DirectorHiring & Retaining Staff Engineers
“Staff engineer interviews must evaluate scope of influence and ambiguity tolerance, not just coding ability”
Org Design
GrowthEngineering Hiring Pipeline
“Employee referrals consistently produce the highest-quality hires with the shortest time-to-close. Build a referral program with meaningful incentives ($5,000-10,000 bonuses are standard at tech companies) and make the process frictionless for referring employees”
530+Articles
27Interactive Tools
16Categories
6Learning Stages
Learning Path
Discover Today
Grafana
Open-source dashboarding and alerting that sits on top of whatever backends you already run
Load Balancer
Distributes incoming traffic across multiple backend servers to prevent overload
Raft Consensus Protocol
Raft decomposes consensus into three relatively independent sub-problems: leader election, log replication, and safety. Each one is tractable on its own, which is the whole reason Raft succeeded where Paxos confused everyone