Scan files and URLs against 70+ antivirus engines.

GCHQ's web app for encoding, encryption, and data analysis recipes.

Interactive course for mastering CSS animations.

Help frogs find lily pads while practicing Flexbox.

Water carrots and grow your CSS Grid skills.

32 levels of CSS selector practice.

Visual, interactive way to learn Git branching.

Free Chinese ebooks in 6-inch PDF, mobi, and epub for e-readers.

Real-time visualization of Python / JS / C++ code to learn algorithms.

Online JSON editor with formatting, diffing, and nested-structure analysis.

Paste JSON, get an interactive node graph you can pan and explore.

Turn JSON, YAML, XML, CSV, or Mermaid into interactive diagrams.

Free, ad-free home workouts, training plans, and fitness challenges.

Pick a muscle on the body diagram to see exercises that target it.