from where to where do you want to use websockets? whatever you can do in js would work. k.js is the interface: env:{read,write,mmap,munmap:O,exit:O,hop:O,hcl:O,now:O,u0c:O,u1c:O,cmd:O,v0c:O,v1c:O,frk:O}
these are functions implemented in js which are called from k(wasm). you can provide implementations for hop/hcl e.g. to do ws connections.

@ngn very nice! we set the initial memory double the size k requests at init. there needs to be more because c needs some (for data and stack). everything below __heap_base is for c, above for k.
Your mmap (in js) needs to grow wasm memory, if the initial size if exceeded. this can be done with: K.exports.memory.grow(n) where n is in 64kb blocks.

@ngn also nice would be to read files from the server, e.g. libraries or data. that could be with io verbs or \l file. i use this:
function load(s){fetch(s+".k").then(r=>{return r.text()}).then(s=>E(strip(s)))} // e.g. \lm

see here: https://github.com/ktye/i/blob/master/_/listbox/listbox#L65
n is a local. js does not project.

there are many interpreters for wasm, but we need to provide an import module, because some things need to be implemented by the embedder.
There is e.g. wasm3 which is a c program and provides a library that could be used.
I use a go library called wagon, that runs my test cases after compiling k.w to wasm: https://github.com/ktye/i/blob/master/_/w/wagon_test.go