Learn to Code

Exercism offers practice and mentoring across 83 programming languages.

DOM Events visualizes the Document Object Model event system through interactive examples.

egghead offers expert-led courses and curated resources for modern web development.

Backend Cheats presents reference material and a white paper for people working on backend software.

Mallet provides machine learning tools for language processing, according to its project title.

This guide demonstrates self-hosted applications that run with Docker.

LearnCS.online provides interactive lessons for learning Java and Kotlin.

ProjectLearn teaches programming through projects across web, mobile, game development, machine learning, and artificial intelligence.

This handbook gathers resources for engineers aiming to develop toward senior engineering roles.

Code.org, now CodeAI, provides free K–12 curriculum and tools for teaching digital fluency, computer science, and AI.

Java Design Patterns offers a reference collection for studying common software design patterns in Java.

Players build infrastructure and scale for traffic in Server Survival, a tower defense game about cloud architecture.

A Python learning playground and cheat sheet organizes example scripts by topic, with explanations for the code.

Scratch Wiki documents the Scratch platform and links to editions of the wiki in multiple languages.

SQL Police Department teaches SQL through online crime-solving missions that require building queries and reviewing results.

TechSchool provides free technology education and programming courses, including Elixir, Python, Ruby, React, and Node.

A collection of DevOps interview questions covers tools and topics including Linux, cloud services, containers, networking, and databases.

The open-source book WebRTC For The Curious explains WebRTC protocols and APIs, summarizing RFCs and undocumented knowledge.

Data Engineering Zoomcamp offers a free nine-week course that teaches data engineering system development.

Full Stack Open is a University of Helsinki course on JavaScript web development, including React, Node.js, and REST APIs.

An open-source initiative, Virgilio guides learners through data science resources and skill development.

MySQL Tutorial provides lessons and reference material for learning MySQL.

StrataScratch offers over 1,000 data science interview questions across SQL, Python, statistics, machine learning, and data projects.

Flexbox Defense uses a game format to help users practice CSS Flexbox layout concepts.