Practice Writing
Complex Software.

Recreate Redis, Git, Docker — with your own hands.
Gain expert-level confidence by taking action and diving deep, learning from the world's best.

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See the 2m demo

Learn to do it right — from the best.

Build complex projects and discover best practices through
expert-reviewed recommended approaches.

JJ Kasper

Maintainer of Next.js

Reviewer for JavaScript

Marcos Lilljedahl

Docker contributor & ex
Head of DevOps @ Vercel

Reviewer for Golang

Juan Campa

Chromium Hacker @ Mighty &
ex Architect @ Zynga

Reviewer for Rust

Stan Lo

Ruby Infra @ Shopify &
Rails contributor

Reviewer for Ruby

Paul Kuruvilla

CTO, CodeCrafters

Solutions Author

Trusted by engineers at top companies with learning budgets

Hear it from our members

Engineers at top teams love The CodeCrafters Way™

These guys ruined my weekend

Djordje Lukic (@rumpl)

Full-time Docker contributor

There are few sites I like as much that have a step by step guide. The real-time feedback is so good, it's creepy!

Ananthalakshmi Sankar

Automation Engineer at Apple

I spent a full day on your Docker building course and ended up building the whole thing myself. As a SRE (and mostly a user of docker), digging into the internals blew me away.

Raghav Dua

SRE at Coinbase

The Redis challenge was a great way to procrastinate sleeping for a week! A good change of pace from my regular work, and allowed me to explore some cool tech. I'll be back for more.

Rahul Tarak

Pioneer.app & ODX1 Fellow

The Redis challenge was extremely fun. I ended up having to read Redis protocol specification doc pretty carefully in its entirety! The result felt like lightly-guided independent study, if that makes sense. (Which, again, was lots of fun)

Charles Guo

Scala Team at Stripe

I'm learning about how Redis works under the hood, system calls, socket programming in Python — something I've never done before

Akshata Mohan

Senior Data Scientist at Cloudflare

I've started the Docker challenge, enjoying it a lot so far. Just the right level of guidance, helpful and still gives you a lot of freedom to explore and learn for yourself.

Maya Farber Brodsky

Recurse Center Participant

My favorite way to master a language.

Pranjal Paliwal

$35k winner of HackAtom

Found out from a colleague. It has you build your own version of things like Git and Docker from scratch. A cool way to build a stronger mental model of how those tools work.

Beyang Liu

CTO at SourceGraph

The Docker challenge helped me dive into its internals, through *actual* practice. Super fun.

Kang Ming Tay

Software Engineer at Supabase

I was really impressed that they support Haskell, and will probably usethis to learn Rust! The git-based workflow is :chefkiss:

Jonathan Lorimer

Lead SWE at Mercury Bank

The instant feedback right there in the git push is really cool. Didn't even know that was possible!

Patrick Burris

Senior Software Developer at CenturyLink

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Explore Challenges

Projects that go
way beyond the basics

The most respected engineers got there by improving the depth of their understanding — and you can too.

Recreate timeless software and experience advanced system design concepts, while developing an appreciation for tools you use everyday.

Most languages supported.

Charles Guo

Scala Team at Stripe

Inspiration directly from
how the experts do it

Reading good code is as important as writing code.

First build the project your way. Then compare with the CodeCrafters approach. And finally, navigate the official source code to see how it's done.

A great headstart into becoming an OSS contributor.