For startup engineers

Build it right the first time.

Your architecture decisions today determine your scaling costs tomorrow. Practice designing systems that grow with your product through interactive exercises.

Start the System Design Course

Ship fast without shortcuts

Learn which architecture decisions matter at your stage and which ones can wait. Practice making the right trade-offs.

Database and scaling patterns

When to shard, when to cache, when to add a queue. Exercises that simulate the scaling decisions startups face at each stage.

Avoid the rewrite

Every startup fears the "we need to rewrite everything" moment. SOLID and DRY principles prevent it. Practice them here.

System Design + SOLID + DRY

Architecture that scales with your company.

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.

Try a Lesson

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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Your next scaling challenge starts here.

Interactive system design exercises built for startup pace.

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