System design basics

Start with the building blocks.

Every large system is built from small, understandable pieces. Learn each one through interactive exercises, then combine them into real architectures.

Start the System Design Course

One concept at a time

Load balancers, caches, queues, databases. Each concept gets its own exercises before you combine them into full designs.

Understand the why

Every architecture choice exists for a reason. Exercises explain when each pattern applies and when it adds unnecessary complexity.

Compose full systems

Once you know the pieces, design complete systems. Each exercise builds on previous ones so your understanding compounds.

System Design Course

From individual components to complete architectures.

Try a Lesson

Write code from lesson one

Every lesson is an exercise you solve in your browser. Real code, real tests, real feedback.

Write a greeting function

main.ts

function greet(name: string) {

return `Hello, ${name}!`

}

Structured progression

Each concept builds on the last. You always know what to learn next.

Multiple exercise types

Quizzes, fill-in-the-blank, matching, and code keep every lesson engaging.

Instant feedback

Submit your answer and see test results in milliseconds.

Learn by doing

Solve exercises in your browser from the first lesson.

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Join over 5,000 learners

Flutter Zero to Mastery

Explore our courses

Pick a course and solve your first exercise.

Dart Course

An interactive Dart course where you code, test, and build apps directly in your browser.

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Flutter Course

An interactive Flutter course where you code, test, and build apps directly in your browser.

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S.O.L.I.D. Course

Learn the principles of how software should be structured, so you can guide AI to build better systems.

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D.R.Y. Course

Learn to identify and eliminate code duplication, making your codebase cleaner and easier to maintain.

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System Design Course

Learn how APIs, databases, caching, and load balancing fit together to build scalable systems.

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Interactive courses

Every lesson is an exercise with instant feedback.

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Systems make sense when you build them piece by piece.

Interactive fundamentals for developers new to system design.

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