OnTheScene

01What it does

OnTheScene connects the systems a fire department already uses - scheduling, CAD, weather, traffic, incidents, tides, power outages, air quality - normalizes them server-side into Postgres, and renders curated pages to station displays and the web. The TV never calls an external API directly; every widget declares a stale-after threshold so outdated operational data is visibly flagged, never silently shown as live.

02What I built

• Admin console SPA with a drag-and-drop page builder, widget catalog, automations, integrations, and display management
• TV player SPA with 26 operational widgets, page rotation, pairing flow, PWA support, and live-map opt-in for six map widgets
• Native Apple TV app (SwiftUI) with pairing, cached snapshots, a rotation engine, and stale-data badges
• 22 Supabase Edge Functions acting as server-side pollers, map snapshot renderers, and a WHEN/THEN automation evaluator
• 36 SQL migrations with row-level security and shared Zod schemas across apps and functions

03Key engineering work

• A rules-engine automation layer (json-rules-engine) with reversible actions and a state journal, so a chief can ask why a page appeared and undo it
• Server-generated map snapshots for six map widgets, with an opt-in live MapLibre mode and careful snapshot lifecycle handling
• Content-aware TV layout authoring: 1080p viewport fit analysis, layout presets, and per-widget resize minimums
• Integration honesty: three of six requested data sources had no usable API, so the plan documented official replacements (NWS, CAL FIRE, NIFC, CalOES) instead of scraping