Product notes
Product updates, new challenges, and improvements, newest first.
Faster first builds
First-time challenge builds became faster, reducing the wait when getting started.
Docker challenge deprecated
Docker was removed from the main catalog while remaining available to learners who had already created a repository.
Spot differences in binary output
Git test output began highlighting the first differing byte to help diagnose binary-format errors.
A deeper guide to RDB files
The RDB extension gained a detailed explanation of the file layout in its second stage.
Build an HTTP server in Zig
The HTTP server challenge added Zig support.
Build Shell in C, C++ or Java
The Shell challenge added C, C++ and Java support.
Clojure dependencies for Redis
Clojure implementations of Redis gained external dependency support.
Build Grep in Gleam
The Grep challenge added Gleam support.
Shell navigation
Add pwd and cd to navigate directories in your shell.
Shell in JavaScript and TypeScript
The June product update reports JavaScript and TypeScript support for the Shell challenge.
Identify oversized submission files
Rejected submissions began listing files over the size limit, for both Git pushes and CLI runs.
Build your own Shell
Initially released in beta, this challenge lets you build a shell with a REPL, command parsing, and built-in commands.
Reading is good.
Doing is better.
Build your own Claude Code, Shell, or SQLite. Understand what’s underneath.