The web, made interactive
Browse 24 interactive simulators, visualizers and playgrounds across 13 web technologies — JavaScript, React, CSS, regex, git, blockchain and more. Every tool runs in the browser — no install, no setup. Just open it and watch the concept come alive.
13 categories
Choose a technology
JavaScript
Watch the engine run your code — scope chains, the event loop, and execution, step by step.
ExploreReact
Components, hooks, props, state and the render lifecycle — visualized.
ExploreCSS
Play your way to mastery of Flexbox and Grid.
ExploreRegex
Build, test and understand regular expressions in real time.
ExploreGit
Branch, merge and rebase without fear — visualized as a graph.
ExploreBlockchain
Mine blocks, sign transactions and break a chain to see why hashing matters.
ExploreData Structures
Insert, split and rebalance B-trees and more — visualized as you go.
ExploreBlock Programming
Snap blocks together to learn programming logic — no syntax required.
ExploreTypeScript
Type, hover and infer — see what the compiler really knows.
ExploreJSX & Babel
See exactly what JSX and modern syntax compile down to.
ExploreSass
Write Sass, see the compiled CSS instantly.
ExploreSVG
Understand the path data and coordinate system behind vector graphics.
ExploreAST
Turn source code into a syntax tree and explore every node.
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