OBS Websocket browser proof of concept

content.js

document.addEventListener("contextmenu", async function(e) {
    const message = e.target.closest('.chat-line__message');
    if (!message) {
        return;
    }
    e.preventDefault();

    const obs = new OBSWebSocket();
    await obs.connect("ws://127.0.0.1:4455", "4tP1Yw7d5FxnnCjI");
  
    await obs.call("SetInputSettings", {
      inputName: "ChatHighlight",
      overlay: true,
      inputSettings: {
        url: "data:text/html,<style>html,body{background:white;}</style>" + message.innerHTML,
      },
    });
    await obs.disconnect();
})

manifest.json

{
  "name": "OBS Chat Highlight",
  "description": "Pin a message to a OBS browser source",
  "version": "1.0",
  "manifest_version": 3,
  "content_scripts": [
    { "matches": ["*://*.twitch.tv/*"], "js": ["obs-ws.min.js", "content.js"] }
  ]
}