Auction notification systems require precise separation of connection, authorization, and subscription data.

A technical architecture guide outlines key principles for building real-time auction notification streams. The core requirement is for servers to accurately distinguish between a connected user and one authorized to receive specific auction updates. This is achieved by keeping separate, observable records for user authentication, subscription state, and auction events. The design prevents stale connections from incorrectly delivering updates and ensures clients can recover correctly after disconnection. The contract must clearly define whether authorization is checked at the time of event publication or during client recovery.