Build classic ASCII games and apps

CavernOS is a retro fantasy terminal for building DOS-era ASCII games, powered by WebAssembly.

Get started

Open-source MIT License. GitHub v0.1.0

Choose your language️

Write your game in any programming language that compiles to raw WebAssembly. Quick-start templates are included for Rust and AssemblyScript.

🌏 Distribute to the web

Build your code once, then distribute via the web. No need to worry about compiling for multiple operating systems. Perfect for game jams and discoverability.

⚡️ Near native performance️

WebAssembly runs your code at near native speeds, even in the browser. With minimal layers between your code and the GPU, a smooth 60 FPS is no problem.

📦 Tiny runtime and build

The web runtime has minimal dependencies and checks in at less than 70kB. Your game can be just as small thanks to WebAssembly.

📐 Pixel perfect rendering

Build your game for your favourite terminal size and it will be automatically scaled to fill the screen in pixel perfect increments, or have your game responsively adjust to the available screen area.

Full and half width fonts

Support for using both full and half width font sprites in the same screen, allowing a square tileset with readable UI - inspired by Cogmind.