Everything in the catalog

Shows commits, branches and merges as a graph while you type git commands in a sandbox.

Markdown editor with a live preview pane that runs in the browser.

Web Audio demo that listens to a microphone or a sample and shows the detected note and cents offset.

Series of games teaching programming with blocks, from mazes to music.

Game narrative design tool for mapping branching dialogue and interactive stories as a node graph.

Write D&D-style brews in Markdown and see them laid out like an official book page, ready for print or PDF.

Shows the TypeScript compiler's syntax tree and type info for code you paste.

Tutorial with an in-page 6502 assembler and emulator that draws to a pixel display.

Move shapes around a grid to see how mild preferences can still produce strongly segregated neighbourhoods.

Turns any text into a unique robot, monster or alien image.

HTML5 player and text pane for transcribing interviews, with keyboard shortcuts to control audio playback.

Encodes SVG markup so it can be used inside a CSS background-image url().

Lints an npm package's package.json and exports so it works across bundlers and runtimes.

Generates parametric boxes, trays and mechanical parts as SVG, DXF or PDF for laser cutting.

Draws and simulates digital logic circuits from gates to CPUs in the browser.

Online diff and merge editor for two documents, backed by a JavaScript library.

Compiles and runs C++ and other languages with many compiler versions and shareable permalinks.

Interactive palette generator that interpolates colors between anchor points in a 3D color space.

Builds stylized QR codes and AI-generated artistic QR images.

Chat with open language models that download into your browser and run on WebGPU without a server.

Web note-taking app that stores Markdown notes locally on your machine.

Single-page resume builder for producing a standard, professional one-page resume.

Visual programming language for sound where you wire nodes together to make synths and music.

Invoice generator that runs fully in the browser; no sign-up, templates, logo and instant PDF export.