WABT (https://github.com/WebAssembly/wabt/ https://github.com/WebAssembly/wabt/) and Binaryen (https://github.com/WebAssembly/binaryen https://github.com/WebAss

WABT (https://github.com/WebAssembly/wabt/ https://github.com/WebAssembly/wabt/) and Binaryen (https://github.com/WebAssembly/binaryen https://github.com/WebAssembly/binaryen) as well as the spec itself (https://github.com/WebAssembly/spec/tree/master/interpreter https://github.com/WebAssembly/spec/tree/master/interpreter) all have interpreters for the WebAssembly language. What they don't have is the same import and export binding mechanisms that the JavaScript engines have. JS engines can bind wasm imports and exports with JS functions. The interpreters that exist today are great for testing implementations or compilers but don't have interesting capabilities to interact with an embedding environment. There have been a few experiments with non-JS embeddings (for example, implementations build on LLVM which could easily define bindings to native functions) but nothing really usable or productized yet.