The underground coding club.
Now at UC Berkeley.
CodeCrafters challenges are now free for UC Berkeley students, alum, and staff — for a full year. Request access with your UC Berkeley email before 31 Sept, 2025. Invest in your craft, stay ahead of AI, build the best version of you.
Backed by incredible engineers
These fine folks believe in the CodeCrafters approach.
Mike Krieger
Co-founder/CTO, Instagram
Arash Ferdowsi
Co-founder/CTO, Dropbox
JJ Kasper
Maintainer of Next.js
Jitendra Vaidya
Co-founder, PlanetScale
Paul Copplestone
Co-Founder, Supabase
Hear it from our members
Engineers at top teams love The CodeCrafters Way™
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
My favorite way to master a language.
Pranjal Paliwal
Winner of HackAtom
I’ve started the SQLite challenge, enjoying it a lot so far. Just the right level of guidance, helpful yet gives you a lot of freedom to explore and learn for yourself.
Cindy Wu
Participant at Recurse Center
In a perfect world, job interviews ask for assignments like CodeCrafters instead of Leetcode.
The best way to refresh your programming language skills and learn something new about Redis, Git, SQLite internals.
Vladislav Ten
Software Engineer at Microsoft
The 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
Found out from a colleague. It has you build your own version of things like Git and SQLite from scratch. A cool way to build a stronger mental model of how those tools work.
Beyang Liu
CTO at SourceGraph
