Rails 8 SolidCable: Database-Backed WebSockets Guide

Rails 8 introduces SolidCable as the default ActionCable adapter, replacing Redis with a database-backed polling approach for WebSocket message delivery. The post covers installation, configuration options (polling interval, message retention, autotrim), real-world usage examples (notifications, dashboards, chat, collaborative editing), Turbo Streams integration, and performance benchmarks. PostgreSQL users can leverage LISTEN/NOTIFY for push-based delivery comparable to Redis up to ~1000 concurrent connections. Key caveats include polling latency (~100ms default), increased database load at scale, and lack of built-in presence tracking. SolidCable is recommended for apps wanting simpler infrastructure without Redis; AnyCable is suggested for very high concurrency scenarios.