CodeShellcodeshell
in-browser editor · zero setup

Learn programming
by writing code.

Task-based courses across 5 languages. Type, run, get checked instantly. Distraction-free, terminal-grade interface.

Browse courses$ start python
~/courses/python/01_hello.py
# task: print Hello, World!
print("Hello, World!")

$ python 01_hello.py Hello, World! ✓ all checks passed

Features

Real Python execution

Your Python code runs FOR REAL inside your browser via Pyodide. No backend, no waiting.

Instant feedback

Every task ships with output checks or pattern checks. Fail fast, fix faster.

Built-in cheat sheets

Each language ships with a quick-reference panel — only what you need to solve the next task.

Pick your language

5 tracks, 50 hand-crafted tasks.

all courses →
77 taskslive exec

Linux Terminal

Master the command line — real shell simulation, no installs.

207 taskslive exec

Cloud Engineering

From the NIST definition to AWS, Docker, K8s and IaC — built for the real job.

100 taskslive exec

Python

Readable, batteries-included, runs in your browser via Pyodide.

82 tasks

JavaScript

The language of the web. Runs everywhere.

78 tasks

C

The portable assembly language. Foundation of modern computing.

78 tasks

C#

Modern, statically typed, runs on .NET. Powers games, web, enterprise.

81 tasks

Rust

Memory safety without garbage collection. Fast and fearless.

60 tasks

SQL

The lingua franca of data. Query anything, anywhere.