Sorry, I didn’t see the messages earlier. Feel free to just tag me in messages if you get blocked. That should get me a notification that I can look sooner.

IIRC the general strategy was to implement different kind of ports as class in ports.js , and kernel.rkt just can just add the wrapper on top that. E.g. the string port is there. I think you can follow implementation of open-input-string for open-input-bytes . So it can be an implementation similar to NativeOutputStringPort , where instead of taking a JS string, it can be an array or even Typed Array (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array) ?