Decker is a multimedia platform that lets users create and share interactive documents with text, images, sound, hypertext, and scripted behavior. It runs in web browsers and has native builds for MacOS, Windows, BSD, and Linux. Decker extends the simplicity of HyperCard while adding features such as deep undo history, scroll wheel and touchscreen support, modern keyboard navigation, and bulk editing operations. Users can employ Decker to produce E‑Zines, organize notes, give presentations, develop adventure games, or create 1‑bit pixel art. The platform features a scripting language called Lil, influenced by Lua and the functional language Q, and includes implicit scalar‑vector arithmetic and an integrated SQL‑like query language. Decker provides built‑in interactive widgets and a mechanism for defining new widgets, which can be copied and pasted through the system clipboard. Documents are stored in a line‑oriented text format that works with version control tools such as Git and SVN. A standalone interpreter named Lilt can process Decker files headlessly and can be compiled into a cross‑platform APE executable for shell scripts. Decker is released under an MIT license, contains no advertising or telemetry, and includes a community forum and scheduled Game Jams. The next Game Jam, Decker Fantasy Camp, is set for July 2026.