Built a Slack-style chat app — no Redis, and Postgres handles the realtime backplane

Hello everyone, happy to share a recent project I've been working on — meet Echo, a team chat app in the Slack family. Why might this interest you? Because the source code is available to read. Echo is an attempt at recreating Slack's feature surface, which includes workspace creation, channels, DMs with file sharing. The ideal choice to build a real-time application is, by default, choosing WebSocket as the transport protocol. But building the system reliably at scale introduced two m