I wrote my first emulator while learning Rust. Then, I wanted to make it available on the universal platform, the web. Using WASM, we'll see how to port a desktop app in pure Rust to a webapp using WASM. We'll survey the WASM ecosystem: tools, crates, and share tips and hurdles found along the way. Most native languages nowadays can be compiled to WASM, and Rust is no exception. Using an emulator written in pure Rust, we'll explore the challenges of porting a desktop Linux app to the web platform. How hard can it be ? Following through the outline of the emulator, we'll go step by step, and expose which crates make that easy, discover how mature is the Rust WASM ecosystem and tools we need to use to port an app.