This is super cool! It seems that endb uses emscripten to compile to WebAssembly, I wonder if they tried WASI or WASIX (https://wasix.org) to target both browser and server environments!
There are other approaches than the one we've taken so far, and we're still experimenting. But for the current demo, we're quite happy with Emscripten. The entire Wasm ecosystem feels pretty darn magical. :)