Some have compared WebAssembly to Java applets; in some ways, they’re very right, but in some ways, they’re very wrong. Eventually I’ll write a post about the wrong, but for now, the right: in some sense, WebAssembly is a different way of accomplishing what the JVM set out to do: it’s a common virtual machine that can be used to build very cross-platform software.

Java Applets and Flash were security nightmares. WebAssembly, on the other hand, piggybacks on the JavaScript VM. All of the effort going into creating its sandbox also applies to Wasm.