Pick a path.
Start free.
You type every line in small guided steps, and a real checker runs your code. Nothing to install.
New to coding
BEGINNERFREE TO START
Learn to code
From your first line of code to solving problems on your own.
BEGINNERFREE TO START
Projects & OOP
Your own cat, grep and sort, then object-oriented programming.
BEGINNERFREE TO START
Build with AI
Clients bring projects. Booly, our AI, builds them. You make sure they work.
Get hired
INTERMEDIATEFREE TO START
Coding interviews
Big O, then the patterns behind the questions interviews ask.
INTERMEDIATEFREE TO START
System design
Design real systems one decision at a time, from caching to Uber.
INTERMEDIATEFREE TO START
AI coding practice
Real tickets in a real codebase, with an AI teammate that makes mistakes.
Also: AI mock interviews, with an AI interviewer and a scorecard.
Build real apps
INTERMEDIATEFREE TO START
Frontend
Build a shop’s storefront: HTML, CSS, JavaScript, then React.
INTERMEDIATEFREE TO START
Backend
Build a shop’s API: routes, SQL, logins, payments and tests.
ADVANCEDFREE TO START
Full-Stack
Join your API and your storefront into one app.
ADVANCEDFREE TO START
Security
Attack your own shop, then close each hole.
Data & AI
INTERMEDIATEFREE TO START
AI Engineering
Build a support assistant: prompts, tools, RAG, evals and agents.
INTERMEDIATEFREE TO START
Machine Learning
Analyze a shop’s data, then predict who buys again.
ADVANCEDFREE TO START
Data Engineering
Build a shop’s data warehouse: pipelines, dbt and Spark.
INTERMEDIATEFREE TO START
SQL & Databases
Window functions, table design and interview questions. Then MongoDB and Redis.
NO CARD NEEDED.