Product notes
Product updates, new challenges, and improvements, newest first.
Guidance when opening a later stage
Opening a stage before you were ready showed a prompt explaining where to start.
Concise code examples and voting
Find highlighted short implementations, vote on examples, and browse them with less page slowdown.
HTTP compression
Extend your HTTP server to compress responses.
TCP Servers in Python
Learn to write a TCP server using Python's socket library.
Understand Redis’s wire protocol
A new interactive RESP concept explains how Redis clients and servers encode commands and replies.
Build SQLite in Gleam
Gleam support expanded to the SQLite challenge.
TypeScript across the challenge catalog
TypeScript support expanded from Redis to the other available challenges, including DNS, with Bun and external packages.
Tests start on the next stage
Completing a stage automatically started tests for the next one, allowing already-working implementations to progress quickly.
Submit from the CLI without Git
The new submit command lets you complete a stage without a separate git add, commit, and push cycle.
JavaScript package support
Use npm packages in JavaScript implementations across the available challenges.
Test the current stage first
Test runs began checking the current stage before earlier stages to return relevant feedback sooner.
Choose when to complete a stage
Passing tests no longer moved you on automatically, leaving time to refactor before marking a stage complete.
Reading is good.
Doing is better.
Build your own Claude Code, Shell, or SQLite. Understand what’s underneath.