A DNS Packet, Taken Apart
A DNS answer can repeat a name without carrying its bytes twice. I built a small Elixir decoder to see exactly where those bytes go, and the interesting part...
Elixir
Everything Before the Click
Every tool my agent had until now could be run twice with no consequence. Adding one that puts something in my actual Amazon cart changed what the code aroun...
Fresh Forever
Three bugs in the same twenty lines, each one created by the fix before it. The last was the good one: two behaviours that are correct on their own, and toge...
Politely Ignored
My MCP server answered tools/list, validated every argument it was handed, and went completely unused. The model preferred its own browser extension, and not...
The Tooltip That Signed Me Out
My agent decided my Amazon session had expired while looking at a page Amazon only serves to people who are signed in. The culprit was a hidden tooltip, and ...
The Page That Never Came Back
Replying to a process that has died costs nothing and tells you nothing. In a pool that lends out browser pages, that silence cost me a page every time it ha...
What a Port Doesn’t Give You
My agent drives a headless browser through a Node process held by a Port. Two guarantees I take for granted in Elixir stop at that boundary, and one of them ...
Let It Crash Stops at stdin
I have been building a personal agent as an MCP server in Elixir, and the transport turned out to be the interesting part. A single malformed request killed ...
Straightforward Auth in Phoenix, 2026 Edition
Back in 2016 I left myself a note: for simple auth in Phoenix, skip Pow and hand-roll it like the book shows. Ten years later the honest answer is different....
The State of Typing in Elixir
Elixir is dynamically typed, but ‘typing in Elixir’ now spans three things: the runtime shape you get from pattern matching and structs, optional typespecs c...
Phoenix LiveView: Interactive Apps Without Writing JavaScript
Phoenix LiveView handles real-time interactivity on the server, so you can build interactive pages without writing a frontend framework. Here’s a small task ...
Prime Target: Generating Prime Numbers in Elixir
A few ways to generate prime numbers in Elixir, from a naive check to a recursive sieve, a lazy infinite stream, and a parallel version with Task.async_strea...
Building an Elixir API with Plug Only
You don’t always need Phoenix. For a small API, Plug alone gives you full control over requests and responses with almost no machinery. Here’s a JSON endpoin...
Easily insert Elixir pipe operator in Emacs
When writing Elixir code you’ll often find yourself typing the pipe operator which is not very convinient. Let’s see how to ease this in Emacs.
Scheduling tasks without external dependencies in Elixir
Elixir and Erlang comes with so much tooling that most of the time you’ll be able to do what you need to without having to depend on any external software.
GenServer with supervision tree and state recovery after crash
You’ve probably heard that in Elixir you should let processes crash rather than trying to catch every possible exceptions. Then, after a crash, you only have...
Adding additional translations in Phoenix using Gettext
Sometimes when you’re writing a Phoenix app you want to split your translation files to avoid having one big file with everything inside but rather having on...