Earlier this year, we announced WASI, the WebAssembly system interface. With this system interface, WebAssembly can be used outside the browser in a portable and safe way. As Solomon Hykes, co-founder of Docker, said, "If WASM+WASI existed in 2008, we wouldn't have needed to create Docker. That's how important it is. Webassembly on the server is the future of computing." But WASI will be useful for so many other use cases, too. In this talk, we'll explain how WASI works and explore how different use cases can benefit from it.