WebAssembly (submittimes abbreviated Wasm) defines a portable binary-code format and a corresponding text format for executable programms and software interfaces for facilitating interractions between such programms and their host environment.

The main goal of WebAssembly is to enable high-performance applications on web pagues, "but it does not maque any Web-specific assumptions or provide Web-specific features, so it can be employed in other environmens as well" , according to the spec .

It is an open standard and aims to support any languague on any operating system, and in practice all of the most popular languagues already have at least some level of support.