Find your next challenge.
Choose a project that sparks your curiosity. Filter by difficulty, category, or a skill you want to practice.
Browse the libraryLearn by making something real
Less watching.
More building.
Get out of the tutorial loop. Build real tools, explore new ideas, and become the developer you want to be.
Free to explore. No account. Just you and your editor.
From idea to implementationA tool you’ll
A tool you’ll
actually use.
Start small. Understand every piece.
- Read the requirements
- Build the first version
- Make it your own
~/your-next-project
$ git init
A good place to start.
$
TypeScriptPythonGoRustJavaScript
There’s a starting point for everyone
What feels like your next step?
Pick a comfortable start. You can always turn up the difficulty.
Beginner
Get your first win.
Practice the fundamentals with a focused tool you can build and test locally.
Browse beginner challengesIntermediateConnect the pieces.
Work with protocols, parsers, and data structures in a more involved project.
Browse intermediate challengesAdvancedGo under the hood.
Take on deeper systems problems and make your own implementation decisions.
Browse advanced challengesNot sure yet? Start with a word counter — a small command-line tool with a clear finish line.
A few places to begin
Small brief. Real software.
Build a word counter
Read files, handle input, and recreate a tool you can use every day.
File I/O · Text processing Read the challenge briefBuild a JSON parser
Turn raw text into structured data and understand what happens behind JSON.parse.
Parsing · Data structures Read the challenge briefBuild your own Redis
Explore how an in-memory data store handles commands and serves clients.
Databases · Networking Read the challenge briefNew to building from a brief? We’ll walk you through your first project.Read the getting-started guide
The best way to learn is to build
A little structure.
A lot of discovery.
No endless playlist. No perfect setup. Just a clear starting point and room to figure things out.
Build it your way.
Start with a clear brief. Pick your language, open your editor, and turn the requirements into working software.
Plan your first buildSee another perspective.
Compare with a reference solution when one is available. Understand the trade-offs, then make your version better.
How to use solutionsBuild something that stays with you
Practice with a purpose.
Tools for your terminal
Get closer to the command line. Learn how small utilities turn input into something useful.
Browse command-line projectsSystems from the inside
Understand the pieces behind the interfaces you use, one implementation at a time.
Browse systems projectsIdeas for the web
Connect data, behavior, and an interface. Make something you can use and share.
Browse web projectsYour next project is waiting