// deep dives into system design,
// tech stacks & DDIA concepts
// for engineers leveling up
An LLM is just text in, text out. Everything that makes it an agent — context, tools, the loop, memory, verification, and guardrails — lives in the harness around it. Why the scaffolding now matters as much as the model.
"After two system design mocks, the real Google onsite felt like a replay. He flagged the exact gaps the interviewers later probed — I walked in knowing what they wanted."
"My resume went from 2 callbacks to 11 in three weeks. The bullet rewrites turned vague tasks into real impact — recruiters finally noticed."
"The system design mock was honestly harder than my actual Amazon loop. By the real thing I was calm, structured, and got the offer."
"I kept bombing behavioral rounds and didn't know why. One session reframed my stories with actual signal and I passed at Microsoft."
"Jumped from a non-FAANG role to a senior position. The feedback was brutally specific — no fluff, just the gaps I needed to close."
"As a new grad I had no idea what 'good' looked like. The resume rewrite plus two mocks got me three offers, including my top choice."
E-commerce, video streaming, ride-share, URL shortener and more. Real interview questions solved end-to-end.
17 articlesDeep dives into the technologies powering modern systems — databases, caches, queues, and APIs compared.
23 articlesCondensed notes and takeaways from Designing Data-Intensive Applications — the SDE interview bible.
12 articlesAI coding tools, prompt engineering, agents, building on LLM APIs, and what it all means for interviews.
10 articlesStreaming (SSE), the GPU inference layer, an LLM gateway, memory & RAG, and the cost tradeoffs.
System DesignChunking, the vector index (ANN), hybrid retrieval, reranking, and grounded answers with citations.
System DesignProduct catalog, cart, inventory, payment processing, and order management at scale.
System DesignGeo-indexing, tile rendering, routing algorithms, and location search at scale.
System DesignCDN strategy, encoding pipeline, chunked delivery, and handling millions of concurrent viewers.
System DesignWebSockets, message fan-out, presence indicators, and real-time delivery at scale.
System DesignGeo-indexing, driver matching, surge pricing, and trip state machine design.
System DesignHash collision handling, redirect latency, analytics tracking, and custom slugs.
System DesignInventory locking, double-booking prevention, search ranking, and payment flows.