There is a standing piece of advice in software: don't reinvent the wheel. It is good advice for shipping and terrible advice for learning, because the fastest way to actually understand a thing is to build a worse version of it yourself and find out where it hurts.
This site is written in that spirit. Long explanations of things most people use without looking inside — how a hash map degrades, what a database index is physically doing, why your async code deadlocks — aimed at working engineers who want the model rather than the recipe.
How hash maps actually work
Buckets, collisions, load factor, and the moment O(1) quietly stops being O(1).
What a database index really is
A B-tree, on disk, and why the wrong column order makes one useless.
Why floating point lies to you
0.1 + 0.2, and the binary reason your invoice totals are eight pence out.
Reading a stack trace properly
The skill nobody teaches, which separates ten-minute bugs from all-day ones.
The bias here
Depth over breadth, and mechanism over API surface. There are already excellent references for what a function does. There are far fewer good explanations of why the thing behaves that way, and those are the ones that keep paying out ten years later when the framework has been replaced twice.
No tutorials that stop at the interesting part. No "in this article we will explore". If a piece cannot say something specific, it does not get published.