Everything in the catalog

Rebuilds an image as pure CSS box-shadows that you can paste into a stylesheet.

Collection of 180 gradients with CSS code and PNG downloads.

Drag-and-drop preview for glTF 2.0 models using three.js.

Open-source page audit that tests front-end quality and performance issues in a page.

Turns an uploaded document image into structured Markdown using a vision model.

QR code generator for URLs, text, Wi-Fi and vCards with styling options and a scanner.

Hear arpeggios by turning chords into running notes, and see their shapes on screen.

Explore how chords are built and move between them, with colors and sound, using simple controls.

Visualize the harmonic overtones of a note and hear how they add up to a timbre.

Click a grid to make short melodies and loops with simple instruments in the browser.

Sketch melodies on a piano roll by painting notes on a grid and play them back.

See how sound waves move and change with pitch, and play a keyboard to hear and view the result.

Pluck virtual strings of different lengths to learn how length changes pitch and harmonics.

Record your voice and spin it on a record to change its speed, pitch and direction.

Free open-source digital audio workstation in the browser for music education and production.

Piano-roll MIDI editor in the browser.

DuckDB SQL shell that runs entirely in the browser via WebAssembly, reading local and remote files.

Makes code snippet images with gradient backgrounds and window chrome.

Generates and interpolates between short melodies and drum patterns using a variational autoencoder in the browser.

Play a few buttons and a neural net turns them into a full piano performance in your browser.

Transcribes piano audio into MIDI notes in the browser using the Onsets and Frames model.

Configurable random test data generator exporting to SQL, CSV, JSON, XML and more.

Draw points, lines and polygons on a map and edit the resulting GeoJSON side by side.

Opens and edits Word, Excel and PowerPoint files and annotates PDFs in the browser, with processing done locally.