Making a WebSocket survive Chrome's Manifest V3

The bug reports all sounded the same. "It disconnected again." No error, no warning, nothing on screen to explain it. Someone would open a GitHub issue, start a planning-poker vote, then stop to actually read the thing they were estimating. Thirty seconds later they'd look back and the room had quietly gone still. Other people's votes weren't showing up, and their own weren't reaching the room. It had simply stopped, without a word. If you've ever built anything real on Chrome's Manifest V3, you can probably guess where this is going. The socket didn't drop because the network hiccupped. It dropped because Chrome reached over and killed the process it was living in. This is the story of that bug, and what it actually takes to keep a WebSocket alive inside a Manifest V3 extension. TL;DR: Manifest V3 runs your background code in a service worker that Chrome terminates after ~30s idle. If your WebSocket lives there, it dies with it, silently. The fix is three parts: a heartbeat so extension activity keeps the worker awake, auto-reconnect that pulls a fresh snapshot so drops are invisible, and a try/catch around every port message because the worker can die between your null-check and the call. Why the socket doesn't live where you'd expect First, some context on how the extension is wired, because it explains why this bug was even possible. It puts a button on GitHub issues and boards. Click it, and a live planning-poker room opens right there in the page. Votes flow over a WebSocket to a Cloudflare Durable Object that owns the room's state. Standard real-time stuff. The obvious place to open that socket is the content script, the code injected into the GitHub page. That's where the UI lives, so why not open the socket right next to it? Firefox is why not. A content script runs in the page's world, which means it inherits the page's Content Security Policy. GitHub ships a strict connect-src , and Firefox enforces it against content scripts. Try to open wss://… from the