System Design Resources & Guides

Free, in-depth system design guides, interview breakdowns, and concept deep-dives — caching, databases, load balancing, message queues, and real case studies.

• The Diagram Is Worthless Now — Field notes · 5 min read
  Everyone's prepping the perfect architecture diagram. AI made that worthless overnight — and quietly rewrote what the system design interview actually scores.
• Spotify Search Had to Match Meaning, Not Words — Case study · 4 min read
  Users remember the idea, not the keywords. Dense retrieval matches meaning — the same retrieval pattern now powering modern AI.
• eBay Built Search for What You Can't Describe — Case study · 4 min read
  Visual search isn’t a special case. It’s the same embed-and-find-neighbors skeleton as semantic search — with a CNN swapped in for the text encoder.
• Uber Built a Router With No Router — Case study · 3 min read
  Ringpop puts sharding and routing inside the app nodes themselves — gossip membership and consistent hashing, no central coordinator.
• Spotify Finds Your Next Song by Being Wrong — Case study · 3 min read
  Exact nearest-neighbor search doesn't scale to billions of vectors. HNSW trades a sliver of accuracy for 10x speed and 4x less memory.