WebAssembly has become an important technology in web development, on the server and client side. In this session, we want to take a look behind the scenes and dive deeper into fundamentals like WebAssembly's stack-based programming model, memory management, and interaction with Wasm hosts. Based on samples in WAT (WebAssembly Text), Rust, and C, Rainer Stropek speaks about core principles of Wasm and WASI. Rainer will show examples in the browser and in WebAssembly hosts like Wasmtime and Wasmer.