Interactive bite-sized lessons that teach you how things actually work under the hood. Not syntax — concepts.
Each lesson walks you through a concept step by step — with questions baked in.
You have a users table with 10 million rows. You run:
SELECT * FROM users
WHERE email = 'alice@example.com';It takes 4.2 seconds. The database has no index on the email column — it reads every single row to find a match. This is called a full table scan.
↑ This is interactive — try answering the question
From DNS lookups to database sharding — the stuff interviews test but courses skip.
while (confused) {
lesson.next();
knowledge++;
}Each lesson is exactly 5 minutes. Read, see a diagram, answer questions, done. Short enough to never skip, deep enough to actually learn.
const author = {
name: "fullstackpeter",
followers: 233_000,
type: "practitioner"
};From @fullstackpeter — 233K+ developers trust the content. Not generic courseware. Real explanations from someone who ships code.
if (confidence < 0.8) {
schedule.review(concept);
// resurface in 2 days
}Spaced repetition resurfaces concepts before you forget them. Rate your confidence — the app focuses on what you almost know.
First 2 tracks free, no card required.
No credit card required for free tracks