System Design
Two million games, one running clock
Plate two: two players sharing one truth while the clock runs, and why the bravest thing a real-time system can do is stop.
AI
Security
Securing GenAI at enterprise scale
Large language models are rarely the weakest part of a GenAI system. The prompts, permissions, tools and people wrapped around them usually are.
Architecture
Answering questions with MCP
This site now answers questions over MCP through a tool called `ask_matt`. It quotes from published articles, hands over the hand-kept numbers when a question wants one, cites everything, and refuses the rest. The refusal took the most design effort.
Engineering Leadership
Interviewing engineers in the age of AI
When every candidate has a world-class assistant in the next tab, the interview stops measuring memory and starts measuring judgement. Most processes haven't noticed yet.
Engineering Leadership
Don't let AI borrow your brain
The danger of AI isn't that it makes engineers less productive. It's that it quietly removes the exercise that kept them sharp in the first place.
Engineering Leadership
AI doesn't change Conway's law
Every technology generation promises to transform how software gets delivered. Most of them eventually rediscover that organisational structure shapes the outcome far more than the tools the engineers happen to be holding.
Engineering Leadership
From novelty to plumbing
The interesting question is no longer whether engineers use AI tools, but where they belong in the workflow and where they quietly make things worse.
System Design
A payment system that refuses to guess
The second in the series: a system where the dangerous failure is not downtime but doubt, and where the guardrails exist to stop the machine resolving that doubt with optimism.
Architecture
Your AI doesn't need another API, it needs a toolbox
Why Model Context Protocol matters less because of the protocol itself and more because it solves a problem every engineering organisation eventually encounters.
Engineering Leadership
What AI adoption actually looks like inside a 300+ engineer organisation
The hardest part of AI adoption isn't choosing tools. It's changing how engineers, leaders and organisations work around them.
System Design
Designing a URL shortener for its worst day
Resilience is a design input, not a deep dive at the end. The first in a series: the smallest system everyone knows, designed around the question of what is allowed to die.
Computer Science
The architecture of a chess engine
A modern chess engine can evaluate millions of positions per second, yet most of its strength comes from surprisingly simple ideas: search, pruning, caching, and a relentless obsession with efficiency.