Everything

PythonBeginner robot

Add hours on a 24-hour clock

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JavaScriptBeginner robot

Add hours on a 24-hour clock

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PythonBeginner robot

Add in parts

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JavaScriptBeginner robot

Add in parts

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JavaScriptBeginner robot

Add two numbers

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JavaScriptBeginner robot

Add up a list

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PythonBeginner robot

All the factors

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JavaScriptBeginner robot

All the factors

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PythonBeginner robot

Binary card values

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JavaScriptBeginner robot

Binary card values

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PythonBeginner robot

Cards from the biggest down

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JavaScriptBeginner robot

Cards from the biggest down

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PythonBeginner robot

Count the even numbers

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PythonBeginner robot

Does it divide?

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JavaScriptBeginner robot

Does it divide?

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PythonBeginner robot

Double it

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JavaScriptBeginner robot

Find the biggest number

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PythonBeginner robot

Greet someone

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JavaScriptBeginner robot

Greet someone

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PythonBeginner robot

How many cards do I need?

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JavaScriptBeginner robot

How many cards do I need?

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PythonBeginner robot

Inside angle of a shape

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JavaScriptBeginner robot

Inside angle of a shape

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PythonBeginner robot

Is it even?

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PythonBeginner robot

Power of a number

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JavaScriptBeginner robot

Power of a number

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PythonBeginner robot

Say hello

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JavaScriptBeginner robot

Say hello

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PythonBeginner robot

Spot a parity error in a row

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JavaScriptBeginner robot

Spot a parity error in a row

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PythonIntermediate alien

Add a parity bit

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PythonIntermediate alien

Add hours on a 12-hour clock

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JavaScriptIntermediate alien

Add hours on a 12-hour clock

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PythonIntermediate alien

Barcode: the last digit

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JavaScriptIntermediate alien

Barcode: the last digit

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PythonIntermediate alien

Book code: the last digit

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JavaScriptIntermediate alien

Book code: the last digit

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PythonIntermediate alien

Count the dots on the cards

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JavaScriptIntermediate alien

Count the dots on the cards

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JavaScriptIntermediate alien

Count the vowels

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PythonIntermediate alien

Count the words

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JavaScriptIntermediate alien

Factorial

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PythonIntermediate alien

Fizz and Buzz

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PythonIntermediate alien

Is it a prime?

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JavaScriptIntermediate alien

Is it a prime?

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PythonIntermediate alien

Leap years

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JavaScriptIntermediate alien

Leap years

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PythonIntermediate alien

Months later

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JavaScriptIntermediate alien

Months later

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PythonIntermediate alien

Name the music note

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JavaScriptIntermediate alien

Name the music note

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PythonIntermediate alien

Palindromes

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PythonIntermediate alien

Prime factors

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JavaScriptIntermediate alien

Prime factors

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PythonIntermediate alien

Reverse the words

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PythonIntermediate alien

Show a number with five cards

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JavaScriptIntermediate alien

Show a number with five cards

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JavaScriptIntermediate alien

Sort a list by hand

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JavaScriptIntermediate alien

Turn text around

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PythonAdvanced astronaut

Add two video lengths

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JavaScriptAdvanced astronaut

Add two video lengths

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JavaScriptAdvanced astronaut

Binary search

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PythonAdvanced astronaut

Card number: the last digit

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JavaScriptAdvanced astronaut

Card number: the last digit

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PythonAdvanced astronaut

Check any barcode

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JavaScriptAdvanced astronaut

Check any barcode

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JavaScriptAdvanced astronaut

Fibonacci, fast

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PythonAdvanced astronaut

Find the flipped card

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JavaScriptAdvanced astronaut

Find the flipped card

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PythonAdvanced astronaut

Find the prime numbers

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PythonAdvanced astronaut

Flatten a list

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PythonAdvanced astronaut

Is this book code real?

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JavaScriptAdvanced astronaut

Is this book code real?

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PythonAdvanced astronaut

Is this card number possible?

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JavaScriptAdvanced astronaut

Is this card number possible?

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PythonAdvanced astronaut

Write a number in binary

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Programming languages Beginner robot

How binary digits work: programming challenges

Difficulty 1/5 On other sites Screen-free lesson

Programming challenges (Scratch, Python or blocks) to go with the 'How binary digits work' lesson, from the 'Binary numbers' unit. Best done with a grown-up.

Programming languages Beginner robot

Parity magic: programming challenges

Difficulty 1/5 On other sites Screen-free lesson

Programming challenges (Scratch, Python or blocks) to go with the 'Parity magic' lesson, from the 'Error detection and correction' unit. Best done with a grown-up.

Programming languages Beginner robot

Product code check digits: programming challenges

Difficulty 1/5 On other sites Screen-free lesson

Programming challenges (Scratch, Python or blocks) to go with the 'Product code check digits' lesson, from the 'Error detection and correction' unit. Best done with a grown-up.

Programming languages Beginner robot

Sending a rocket to Mars: programming challenges

Difficulty 1/5 On other sites Screen-free lesson

Programming challenges (Scratch, Python or blocks) to go with the 'Sending a rocket to Mars' lesson, from the 'Kidbots' unit. Best done with a grown-up.

Programming languages Beginner robot

The Modulo operator Unplugged: programming challenges

Difficulty 1/5 On other sites Screen-free lesson

Programming challenges (Scratch, Python or blocks) to go with the 'The Modulo operator Unplugged' lesson, from the 'Kidbots' unit. Best done with a grown-up.

Programming languages Beginner robot

2D breakout game using Phaser

Difficulty 2/5 On other sites Build project

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Beginner robot

30 Seconds of Code

Difficulty 2/5 On other sites Resource list

Code snippets you can understand in 30 seconds.

Programming languages Beginner robot

A Simple Web Server

Difficulty 2/5 On other sites Build project

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Beginner robot

Adventures in Rust: A Basic 2D Game

Difficulty 2/5 On other sites Build project

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Beginner robot

Build a simple 2D physics engine for JavaScript games

Difficulty 2/5 On other sites Build project

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Beginner robot

Code a 2D Game Engine using Java - Full Course for Beginners

Difficulty 2/5 On other sites Build project

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Beginner robot

CSS Learning

Difficulty 2/5 On other sites Resource list

Mainly about CSS – the language and the modules.

Programming languages Beginner robot

From NAND to Tetris: Building a Modern Computer From First Principles

Difficulty 2/5 On other sites Build project

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Beginner robot

How To: Augmented Reality App Tutorial for Beginners with Vuforia and Unity 3D

Difficulty 2/5 On other sites Build project

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Beginner robot

Hydrogen

Difficulty 2/5 On other sites Resource list

Edge-first framework for building Shopify storefronts with React.

Programming languages Beginner robot

Introduction to Ray Tracing: a Simple Method for Creating 3D Images

Difficulty 2/5 On other sites Build project

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Beginner robot

JavaScript Learning

Difficulty 2/5 On other sites Resource list

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Beginner robot

jQuery

Difficulty 2/5 On other sites Resource list

Easy to use JavaScript library for DOM manipulation.

Programming languages Beginner robot

Make Your Own Simple Interpreted Programming Language

Difficulty 2/5 On other sites Build project

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Beginner robot

Offline-First

Difficulty 2/5 On other sites Resource list

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Beginner robot

Tailwind CSS

Difficulty 2/5 On other sites Resource list

Utility-first CSS framework for rapid UI development.

Programming languages Beginner robot

Think like a programmer: How to build Snake using only JavaScript, HTML & CSS

Difficulty 2/5 On other sites Build project

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Beginner robot

V

Difficulty 2/5 On other sites Resource list

Simple, fast, safe, compiled language for developing maintainable software.

Programming languages Beginner robot

VBA

Difficulty 2/5 On other sites Resource list

An event-driven version of Visual Basic 6.0 built into most Microsoft Office apps for automation and scripting.

Programming languages Beginner robot

Craft CMS

Difficulty 2/5 On other sites Resource list

Content-first CMS.

Programming languages Intermediate alien

Build your own 8-Ball Pool game from scratch

Difficulty 3/5 On other sites Build project

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

Canvas

Difficulty 3/5 On other sites Resource list

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

CSS

Difficulty 3/5 On other sites Resource list

Style sheet language that specifies how HTML elements are displayed on screen.

Programming languages Intermediate alien

Education

Difficulty 3/5 On other sites Resource list

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

Esolangs

Difficulty 3/5 On other sites Resource list

Programming languages designed for experimentation or as jokes rather than actual use.

Programming languages Intermediate alien

Flexbox

Difficulty 3/5 On other sites Resource list

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

HTML5

Difficulty 3/5 On other sites Resource list

Markup language used for websites & web apps.

Programming languages Intermediate alien

Learning

Difficulty 3/5 On other sites Resource list

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

Learning

Difficulty 3/5 On other sites Resource list

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

Lua

Difficulty 3/5 On other sites Resource list

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

Playgrounds

Difficulty 3/5 On other sites Resource list

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

Python

Difficulty 3/5 On other sites Resource list

General-purpose programming language designed for readability.

Programming languages Intermediate alien

SVG

Difficulty 3/5 On other sites Resource list

XML-based vector image format.

Programming languages Intermediate alien

Web Accessibility

Difficulty 3/5 On other sites Resource list

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

Web Animation

Difficulty 3/5 On other sites Resource list

Animations in the browser with JavaScript, CSS, SVG, etc.

Programming languages Intermediate alien

Web Design

Difficulty 3/5 On other sites Resource list

For digital designers.

Programming languages Intermediate alien

A 3D Modeller

Difficulty 3/5 On other sites Build project

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

A DIY guide to build your own React

Difficulty 3/5 On other sites Build project

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

A Neural Network in 11 lines of Python

Difficulty 3/5 On other sites Build project

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

A Template Engine

Difficulty 3/5 On other sites Build project

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

ActionScript 3

Difficulty 3/5 On other sites Resource list

Object-oriented language targeting Adobe AIR.

Programming languages Intermediate alien

Amazon Web Services

Difficulty 3/5 On other sites Resource list

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

Android UI

Difficulty 3/5 On other sites Resource list

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

Angular

Difficulty 3/5 On other sites Resource list

App framework.

Programming languages Intermediate alien

Ant Design

Difficulty 3/5 On other sites Resource list

Enterprise-class UI design language.

Programming languages Intermediate alien

Apache Wicket

Difficulty 3/5 On other sites Resource list

Java web app framework.

Programming languages Intermediate alien

AR Portal Tutorial with Unity

Difficulty 3/5 On other sites Build project

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

Aurelia

Difficulty 3/5 On other sites Resource list

App framework.

Programming languages Intermediate alien

AutoHotkey

Difficulty 3/5 On other sites Resource list

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

AutoIt

Difficulty 3/5 On other sites Resource list

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

AVA

Difficulty 3/5 On other sites Resource list

Test runner.

Programming languages Intermediate alien

Backbone

Difficulty 3/5 On other sites Resource list

App framework.

Programming languages Intermediate alien

BEM

Difficulty 3/5 On other sites Resource list

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

Biological Visualizations

Difficulty 3/5 On other sites Resource list

Interactive visualization of biological data on the web.

Programming languages Intermediate alien

Blazor

Difficulty 3/5 On other sites Resource list

.NET web framework using C#/Razor and HTML that runs in the browser with WebAssembly.

Programming languages Intermediate alien

Browser Extensions

Difficulty 3/5 On other sites Resource list

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

Browserify

Difficulty 3/5 On other sites Resource list

Module bundler.

Programming languages Intermediate alien

Build your own 3D renderer

Difficulty 3/5 On other sites Build project

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

Build Your Own Module Bundler - Minipack

Difficulty 3/5 On other sites Build project

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

Building a frontend framework, from scratch, with components (templating, state, VDOM)

Difficulty 3/5 On other sites Build project

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

Building A Python-Based Search Engine

Difficulty 3/5 On other sites Build project

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

Building Blocks for Web Apps

Difficulty 3/5 On other sites Resource list

Standalone features to be integrated into web apps.

Programming languages Intermediate alien

C/C++

Difficulty 3/5 On other sites Resource list

General-purpose language with a bias toward system programming and embedded, resource-constrained software.

Programming languages Intermediate alien

CakePHP

Difficulty 3/5 On other sites Resource list

PHP framework.

Programming languages Intermediate alien

Capacitor

Difficulty 3/5 On other sites Resource list

Cross-platform open source runtime for building Web Native apps.

Programming languages Intermediate alien

Charting

Difficulty 3/5 On other sites Resource list

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

choo

Difficulty 3/5 On other sites Resource list

App framework.

Programming languages Intermediate alien

Chrome DevTools

Difficulty 3/5 On other sites Resource list

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

Clojure

Difficulty 3/5 On other sites Resource list

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

CMake

Difficulty 3/5 On other sites Resource list

Build, test, and package software.

Programming languages Intermediate alien

Coding a Rogue/Nethack RPG in C

Difficulty 3/5 On other sites Build project

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

Coding A Sudoku Solver in C

Difficulty 3/5 On other sites Build project

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

ColdFusion

Difficulty 3/5 On other sites Resource list

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

Composer

Difficulty 3/5 On other sites Resource list

Package manager.

Programming languages Intermediate alien

Continuous Integration System

Difficulty 3/5 On other sites Build project

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

Cordova

Difficulty 3/5 On other sites Resource list

JavaScript API for hybrid apps.

Programming languages Intermediate alien

Critical-Path Tools

Difficulty 3/5 On other sites Resource list

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

Cross-Platform

Difficulty 3/5 On other sites Resource list

Writing cross-platform code on Node.js.

Programming languages Intermediate alien

D

Difficulty 3/5 On other sites Resource list

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

D3

Difficulty 3/5 On other sites Resource list

Library for producing dynamic, interactive data visualizations.

Programming languages Intermediate alien

Dart

Difficulty 3/5 On other sites Resource list

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

Dash

Difficulty 3/5 On other sites Resource list

Python web app framework.

Programming languages Intermediate alien

Data Science

Difficulty 3/5 On other sites Resource list

Data analysis and machine learning.

Programming languages Intermediate alien

Deno

Difficulty 3/5 On other sites Resource list

A secure runtime for JavaScript and TypeScript that uses V8 and is built in Rust.

Programming languages Intermediate alien

Design and Development Guides

Difficulty 3/5 On other sites Resource list

A free resource picked by the open-source community. Open it to see what's inside.

Programming languages Intermediate alien

Design systems

Difficulty 3/5 On other sites Resource list

Collection of reusable components, guided by rules that ensure consistency and speed.

Programming languages Intermediate alien

Dojo Toolkit

Difficulty 3/5 On other sites Resource list

JavaScript toolkit.

Programming languages Intermediate alien

Draft.js

Difficulty 3/5 On other sites Resource list

Rich text editor framework for React.

Programming languages Intermediate alien

Dropwizard

Difficulty 3/5 On other sites Resource list

Java framework.

Programming languages Intermediate alien

Drupal

Difficulty 3/5 On other sites Resource list

Extensible PHP-based CMS.

Programming languages Intermediate alien

Electron

Difficulty 3/5 On other sites Resource list

Cross-platform native desktop apps using JavaScript/HTML/CSS.