Practice real-world coding in bite-sized codebases.
Sharpen engineering judgement, fix tickets, and get reviewed like a junior developer.
Start Ticket
How it Works
Get a Ticket
Practice realistic bugs and feature requests.
Work in a Bite Sized Codebase
Work inside a small React / TypeScript codebase with tests.
Get PR-style review
Submit your solution and get senior-dev style feedback.
Mission
No one should learn engineering judgment for the first time on the job.
AI can generate code.
But great engineers still need to debug messy systems, understand tradeoffs, review changes critically, and make safe decisions inside real codebases.
Moss trains the skills that are hardest to automate: reasoning through unfamiliar systems, identifying root causes, working within constraints, communicating decisions, and knowing when code is correct, dangerous, or over-engineered.
Students do not need more toy problems.
They need practice navigating ambiguity, reviewing AI-generated code, understanding existing systems, and building the judgment real engineering teams depend on.
Our mission is to help aspiring developers become engineers people can trust — before the stakes are real.
