If your app needs to push live updates to connected clients — a job progress bar, a balance that changes when a background worker finishes, a "this record was deleted elsewhere" toast — the reflex is to reach for Redis Pub/Sub or a message broker. But if you already run PostgreSQL, it ships with a pub/sub primitive built in: LISTEN / NOTIFY . No extra infrastructure, no extra failure domain. What is Postgres LISTEN/NOTIFY? It's a built-in pub/sub mechanism: one session runs pg_notify(ch...