🤯 CodeCrafters — Advanced code challenges for senior engineers →

We help engineers get really good at their craft. Build your own Redis, Git, Docker, SQLite from scratch. Become a top engineer.

Hey everybody — it’s Sarup and Paul, the founders of CodeCrafters.io.

We once built our own Git from scratch

And ever since, we’ve been obsessed with how popular devtools work.

We’d binge on books, blogs, videos to learn the internals of Docker, Redis, SQLite… but it just never felt adequate. Nothing could really provide us with the same level of confidence as building an actual project.

So we created the experience we wanted

We launched 4 hands-on challenges of the Build-your-own-X format on our site, and had 1000s of engineers go through them. We also began maintaining GitHub’s 15th most ⭐️ repo, build-your-own-x.

Turns out, it’s a great way to master languages

Senior engineers don’t come across many resources suitable for their skill level, so especially for them, CodeCrafters was a worthy investment of time. In addition to learning about how various devtools worked, they were:

  • Advancing their language skill (e.g idiomatic approaches)
  • Learning to design and refactor large code in a robust manner
  • Bonding with their teammates as they discussed approaches

So we re-imagined the learning experience

The experience is now organised around languages. The challenges now come with recommended approaches from language experts. Once you implement a feature, you can ask — how would a Pro do it?

Engineers at companies like GitHub take advantage of their L&D budget to pay for CodeCrafters. To support teams that care about investing in their growth, we’ve introduced Private Leaderboards, a Slack app, and expensing workflows.


We can’t wait to help teams bond and grow with CodeCrafters.

  • Engineer? Give CodeCrafters a shot, in your favorite language!
  • Work in Engineering Enablement? I’d love to learn about the different education initiatives at your company
  • Well-wisher / existing customer? Please send us a hi! It’s what keeps us going.

I can be reached at sarup@codecrafters.io and over Twitter.


P.S. Think we’re the only ones crazy to build our own Git for fun?

We asked Pete Koomen, co-founder of Optimizely, about how he’s learning Rust.