No Redis, No Kafka: I Built a Real-Time Auction System with Just PostgreSQL

TL;DR: PostgreSQL's LISTEN / NOTIFY system can power real-time features without Redis or Kafka This tutorial walks through a full auction system: live bids, countdowns, item broadcasts, and discontinuation events A single trigger function fans out to every connected browser via Socket.io — Postgres does the heavy lifting 55.6% of developers already use PostgreSQL (Source: Stack Overflow Developer Survey, 2025) — you probably already have it in your stack You're watching a live auction. The price just changed — $1,240, then $1,300, then $1,450 in eight seconds. Behind the scenes, no message broker is running. No Redis cluster. No Kafka topic. Just Postgres. I read Adam's brilliant post about building real-time chat with just PostgreSQL and pg_notify and had one thought: can I take this further? Can I build a full auction system — live bids, countdown timers, live item broadcasts, auction discontinuation — all without a single extra service? Turns out you can. This is how I did it. The A