What problem does it solve? Adding live data to an application fails in production when connection lifecycle, back-pressure, and state reconciliation after disconnect are not designed up front. This Skill provides production-grade patterns for WebSocket and SSE systems so these problems are solved architecturally before the first socket handler is written. ## Core Features & Use Cases - Transport Selection: Decision table for choosing SSE versus WebSocket based on data flow direction, covering job progress, presence, collaborative editing, and live dashboards. - SSE Implementation: Next.js route handler streaming BullMQ job progress with bounded connection caps, 15-second keep-alive pings, and exponential-backoff reconnect on the React client. - WebSocket Presence Server: Fastify-compatible presence server with JWT auth at connection time, room-based broadcast, and a 30-second dead-connection reaper. - Optimistic UI and Reconciliation: React useOptimistic rollback patterns plus version-stamped state reconciliation after reconnect. - Use Case: Stream SwarmX agent pipeline status or BullMQ job progress to a live dashboard, with slow consumers isolated via a bounded broadcaster that drops oldest events instead of blocking producers. ## Quick Start Use the real-time-systems-architect skill to stream BullMQ job progress to my Next.js dashboard over SSE with reconnect handling.
