Earlier quoted context omitted.
Thanks! The hard part was actually understand Chrome extension's lifecycle and communication between the content script, popup, and service worker. What I initially thought was going to be hard, ended up being actually quite easy (cf socket.io). Good luck if you ever attempt to build it :)
I can imagine, browser extensions are a pain in the butt. Are you planning to open source the code? Did you build everything by yourself or on top of https://liveblocks.io/ ?
I was planning on open-sourcing the extension itself, but not the backend for now because of some secrets. But ultimately, my goal is to create a blog post to create a minimal yet functional Chrome extension connected to a backend with socket.io.
And didn't knew this service existed, so created everything myself so far.