Decker: A Modern HyperCard for the Web and Desktop

Decker is a multimedia platform for creating and sharing interactive documents. It builds on the legacy of HyperCard and the visual aesthetic of classic MacOS, but adds modern features like deep undo history, scroll wheel and touchscreen support, and bulk editing. The platform is free, open-source under the MIT license, and available on GitHub.

Anyone can use Decker to create E-Zines, organize notes, give presentations, build adventure games, or doodle 1-bit pixel art. Finished decks can be saved as standalone .html documents that self-execute in a web browser, and can be shared anywhere you can host or embed a web page. Decker also runs natively on macOS, Windows, BSD, and Linux.

The Lil Scripting Language

Decker features a novel scripting language named Lil, influenced by Lua and Q. Lil is easy to learn for beginners but includes powerful features like implicit scalar-vector arithmetic and an integrated SQL-like query language. Here's a simple Lil example that adds two numbers and prints the result:

x: 5
y: 10
sum: x + y
print sum

Lil also supports vector operations:

numbers: 1 2 3 4 5
doubled: numbers * 2
print doubled

This outputs 2 4 6 8 10. The integrated query language lets you filter data like SQL:

table: ["name" "Alice" "Bob"; "age" 30 25]
older: select from table where age > 28
print older

Widgets and Reusability

Decker provides a small collection of built-in interactive widgets for building interfaces, as well as a facility for defining new ones. Custom widgets and their definitions can be copied and pasted using the system clipboard, making them shareable anywhere you can share or store text. Every deck is a toolkit of reusable parts that can be harvested and repurposed for another project.

Command-Line Friendly: Lilt

When built from source, Decker comes with Lilt, a standalone Lil interpreter. Lilt can read, write, manipulate, and even execute Decker documents headlessly. It has even fewer dependencies than Decker itself and can be compiled as a cross-platform APE executable, ready for writing run-anywhere shell scripts. There's even a Lil interpreter that runs on POSIX AWK. Decks are stored in a line-oriented text format that works well with Git and SVN.

Examples and Documentation

Decker includes a guided tour and examples covering draggable objects, sound, color, brushes, fonts, transitions, and more. There are also full game examples like Sokoban and Breakout, and a CHIP-8 interpreter. Libraries include plotting, statistical math, PDF export, Twine file import, animation helpers, easing functions, arbitrary-precision integers, visual-novel modals, sprite animation, grid pathfinding, vector fonts, and sound effect generation.

Documentation includes a reference manual, the Lil programming language guide, the Decker document format, a "Learn Lil in 10 Minutes" tutorial, a Lil playground, a quick-reference card, and Lilt terminal instructions.

Privacy and Autonomy

Decker includes no advertising, telemetry, gamification, or slop-generator integration. The project encourages sharing and building things that make you happy.

How to Get Started

To try Decker now, visit beyondloom.com/decker and use it in your browser. For native installation, download binaries from Itch.io for macOS and Windows, or build from source on Linux/BSD. The source code and bug tracker are on GitHub. Decker also holds themed "Game Jams" every July and December; the next one is Decker Fantasy Camp in July 2026.