Design Uber / a Ride-Hailing System - System Design
“Design Uber” sounds like a CRUD app with a map on top. A rider taps a pin, a driver shows up, money moves. The interviewer lets you believe …
Read MoreSpec-Driven Development - Writing the Spec Is Writing the Code Now
The most productive engineers I know stopped bragging about how fast they type. When a coding agent can produce 400 lines of correct code …
Read MoreChoosing an Embedding Model in 2026 - It's Not the Leaderboard
Most teams pick an embedding model the same way they pick a sorting algorithm: look up the benchmark, take the top result, ship it. For …
Read MoreDesign a URL Shortener (TinyURL) - System Design
Everyone thinks the URL shortener is a trivial problem. “It’s a hash map. Store long URL, return short URL, done.” Then the interviewer …
Read MoreDesign Twitter's News Feed - System Design
The Twitter timeline looks trivial until you say the numbers out loud. “Show me a list of tweets from people I follow, newest first.” It is …
Read MoreDesign WhatsApp / a Chat Messaging System - System Design
A chat app sounds like the easiest system you will ever build. “User A sends a message, user B receives it.” One INSERT, one SELECT. The …
Read MoreMulti-Agent Systems - When Splitting the Work Actually Helps
The instinct when a task is complex is to throw more agents at it. Spin up a researcher, a writer, a critic, a planner - a whole crew. It …
Read MoreObservability for LLM Apps - You Can't Fix What You Can't Trace
When your web service throws a 500, you have a stack trace. When your LLM app returns a bad answer, the status code is 200, the latency …
Read MoreSemantic Caching - The Cheapest 40% Off Your LLM Bill
The cheapest optimization most teams skip is not routing to smaller models or trimming the context window. It is not calling the model at …
Read MoreStructured Outputs - Stop Parsing LLM JSON by Hand
If you have a regex somewhere that strips markdown fences to pull JSON out of an LLM response, you have a time bomb. It works 95% of the …
Read MoreContext Engineering - The Discipline That Replaced Prompt Engineering
The question engineers ask most often when an LLM pipeline underperforms is: “how should I reword this prompt?” That is almost never the …
Read MoreSmall Language Models Are Eating the Easy 80%
Most production AI costs are paid to frontier models for tasks that a 3-billion-parameter model running locally could handle just as well. …
Read MoreDiffusion LLMs - The Text Models That Don't Predict Left to Right
Every LLM you have used in production generates text the same way: one token at a time, left to right, each token depending on everything …
Read MoreWhat 'Thinking' Actually Costs - Reasoning Models and Test-Time Compute
When you enable extended thinking on Claude or switch to an o-series model, the price per request jumps 3 to 10x. That is not because you …
Read MoreYour AI Agent Is a Security Hole - Prompt Injection in 2026
Most engineers building agents spend time worrying about hallucinations. The more immediate risk is that your agent will faithfully execute …
Read MoreYou're Shipping AI Features Blind - Eval-Driven Development in 2026
The dirty secret of most AI product teams in 2026: when someone asks “how do you know the new prompt is better?” the honest answer is “we …
Read MoreHow AI Agents Actually Remember - Memory Architectures in 2026
Ask anyone building agents what their biggest problem is and “memory” comes up within the first two sentences. The agent solved the bug …
Read MoreAI-First Development Is Not Vibe Coding - Here Is the Difference in 2026
The term “vibe coding” entered the vocabulary in early 2025. The idea: describe what you want, let the AI write it, accept the output, …
Read MoreBuilding AI Agents That Actually Work in Production in 2026
Every AI framework promises agents that can “autonomously complete complex tasks.” The demo shows an agent booking flights, writing code, …
Read MoreBuilding Custom Skills for Claude Code - The No-Code Way to Extend AI in 2026
Claude Code has a plugin system that requires no code. Skills are markdown files that live in ~/.claude/skills/ and define reusable …
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