A self-paced course
Built to take you
all the way to
software engineer.
No cohort, no deadlines, no semester. Start when you want, stop when you need to, and pick it up where you left off.
You typed .legnth. Most programs show you a red X and a failed test, and you are on your own from there. Here you get a clear picture of what went wrong and why: a misspelled property is undefined, arithmetic on undefined gives NaN, so your loop never ran once. And if you don't know what that means, you're in the right place.
See it in action
This is a real exercise from the course. Edit it, run it, and see what happens when you get something wrong.
A coin was flipped several times, and the results were recorded in an array like ["heads", "tails", "heads"].
Write a function countHeads that takes that array and returns how many times the coin came up heads.
The code is not the hard part anymore
AI will write the function now. It'll also write one that looks right, and you're the one who has to catch it if it's wrong. That skill comes from building it yourself, slowly, with something telling you exactly why it broke and what to try next.
It already knows how you're going to get stuck
Each exercise carries the specific mistakes people make on it, written down in advance from years of watching students hit the same walls. So when you get one wrong, it already has something to say about that exact mistake.
Built for having nobody to ask
Hints whenever you need them, guilt-free. Every unfamiliar term defined one hover away. And when you're truly stuck, there's a way forward, because being trapped is what makes people quit.
Deep first, then wide
Instead of forty hours of video across six languages, this starts with JavaScript and stays there, because JavaScript runs on both the front end and the back end. 44 lessons and 56 exercises, each short enough to finish in one sitting. The road runs all the way to full-stack, one module at a time.
Built on how people actually learn
Retrieval over rereading, spacing over cramming, recall over recognition. Each of those comes from research, and the page behind this link names every study it leans on. How this works
Where this comes from
I'm Gonzalo Romero. I have been teaching since 2011, computer science since 2017, and more than five hundred students have come through my classes. They now write software at Bloomberg, Microsoft, Datadog, JPMorgan and more than a dozen other places.
It's being built in the open, and it isn't done. JavaScript now, full-stack as the modules ship, every part built the way this one was. The first two chapters are free, and they're enough to tell you whether it works for you. If it does, you can join now, at the lowest price this will ever be.
Free to start. No card.