Everything in the catalog

Run TIC-80 fantasy computer carts in the browser, a tiny retro console for homebrew games.

Builds scripts that harden privacy and security settings on Windows, macOS and Linux, chosen by checkbox.

Draw boxes, arrows and lines on a text grid to make diagrams you can paste into code comments or READMEs.

Draws a JavaScript regular expression as a railroad-style diagram to help you read it.

Compares Amazon EC2 instance types by specs and price across regions.

3D walk-through of the computations inside a small GPT-style language model.

JupyterLab running entirely in the browser with a WebAssembly Python kernel, no server needed.

Create a meeting poll with candidate dates and share the link; no login needed for voters.

Edit SVG path data as text or by dragging points, with relative and absolute commands.

Plain-text publishing page where you write and post a piece to a public URL, with anonymous posting.

Browser MQTT 5.0 client that connects over WebSocket to publish and subscribe to topics.

Open-source web app that writes privacy policies and terms of use for mobile and web apps.

Write dated events in plain text and view them as a timeline, calendar or Gantt chart.

Typing practice that adapts lessons to your weakest keys as you type.

Block-based programming editor for making games, stories and animations, usable without logging in.

Shows what the compiler generates behind C++ features by expanding your code into explicit source.

Drag-and-drop section templates and a Markdown editor for assembling a project README.

Lints GitHub Actions workflow files in the browser using the WebAssembly build of actionlint.

Shows your public IP address with country, city and ASN details.

Playground for the Viz.js library that renders Graphviz DOT to SVG entirely with WebAssembly.

Converts ASCII art diagrams into clean SVG graphics.

Edit, simplify and convert geographic data such as Shapefile, GeoJSON and TopoJSON in the browser.

Turns a pasted GitHub repository URL into an interactive map of the code's architecture.

Opens 3D model files such as OBJ, STL, 3DS and glTF in the browser, with local processing noted on the page.