About
I'm Nikola Roganović. I write about how tech works inside, with animations you can pause and play with.
Why animations
Most explanations of how software behaves are a box, an arrow and another box. That's fine for showing what talks to what. It doesn't show what happens over time, or when a lot of traffic shows up, and that's usually the interesting part. So every article here is built around animations you can pause, and in most of them you can change what goes in.
The first article, 100 requests per minute, and 200 got through, is a good example. It starts with a rate limiter set to 100 per minute that lets 200 through, and the rest of the article is about why.
How they're made
I built my own animation engine for this. It works out each step of an algorithm and draws it in pencil, so what you see is what the algorithm actually does. The short videos I post on LinkedIn and YouTube come out of the same engine.
The first articles are in pencil. Later ones might look different when a topic suits another style better, like a blueprint or a chalkboard. One article always stays in one style.
Sections
Articles go under four sections: System Design, Under the Hood, Beautiful Data and Interview questions. Topics marked Soon are ones I'm working on, and they can still change.
Sources and mistakes
When I say something about a real company, standard or tool, I link to where it comes from, and the sources are listed at the end of each article. If something turns out to be wrong, I fix it and add a dated note at the end of the article, so you can see what changed.
Working together
If you make a developer tool and want an article like this about your product, have a look at For companies.