latency-critical-systemslisted

# Latency Critical Systems (Laravel) Engineering approach for latency-sensitive Laravel paths: realtime dashboards, streaming, ingest workers, queues, caches, and execution gateways where p95 latency and freshness matter. This skill is engineering-focused; it does not authorize live trading or financial advice. ## Constraints - Apply `@rules/sql/optimalize.mdc` for every query on the hot path (N+1, eager loading, index usage, batching) - Apply `@rules/laravel/laravel.mdc` for framework-level structure and caching choices - Apply `@rules/laravel/queue-debouncing.mdc` when smoothing bursty queue work - Measure, do not guess — every claim about latency must come from a real readback. - Never trade correctness for speed (see Guardrails). ## Use when - A page, API route, broadcast, or dashboard must hit a latency target (p95/p99). - Queue lag, cache staleness, or freshness age is a visible problem. - Streaming / websocket freshness or execution-gateway timing is in scope. - You are deciding where to cache, batch, replicate, or move compute. ## 1. Split the metrics Do not collapse everything into "fast." Track separately: - p50, p95, p99 latency (one slow tail dominates user perception); - throughput (requests/jobs per second); - freshness age (how old the displayed data is); - queue depth and queue wait time; - cache hit rate; - provider/external API response time; - browser render time; - correctness under load; - failure and retry behavior. Capture them with real tools: r