Realtime chat without WebSocket: long-polling, reconnection races, and duplicate push notifications

▤ Summary

This article explains how to build realtime chat without WebSocket by using long-polling, reconnection control, and duplicate-delivery protection. It walks through request lifecycle handling, request UUID checks, and cancellation logic to avoid race conditions and stale responses. It also covers retry strategy design with exponential backoff and full jitter, plus app-state and connectivity checks to decide when to resume polling. The article finishes with practical data-parsing and observer-management patterns for keeping message delivery consistent.

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