Environment Variables

All configuration is loaded via a .env file in the project root. Copy .env.example to .env and populate each value before starting the server.

Reference

Variable	Required	Description
NODE_ENV	No	development or production. Affects logging behavior.
PORT	No	Server listen port. Defaults to 3000.
CESIUM_ION_TOKEN	Yes	Cesium Ion access token. Needed for Google 3D Tiles (asset #2275207). Get one at ion.cesium.com.
TOMTOM_API_KEY	Yes	TomTom Maps API key for live traffic tiles. A fallback key is hardcoded but may be rate-limited. Get one at developer.tomtom.com.
AIRNOW_API_KEY	Yes	AirNow API key for real-time AQI data. Free registration at docs.airnowapi.org.
NY511_API_KEY	No	511NY API key. Used by the /ny511-cameras proxy endpoint (not the primary camera source).
TRAFFIC_VIEW_API_KEY	Yes	TrafficView API key for FDOT CCTV cameras. Used by /fdot-cameras.
EM_FIREBASE_API_KEY	Yes	Firebase Web API key for the Emergency Management project (CORD2). Used to obtain an anonymous Firebase ID token to authenticate CORD2 Cloud Function calls.
FIREBASE_SERVICE_ACCOUNT_JSON	Yes*	Full Firebase Admin service account JSON as a single-line string. Used in production/Render for CO₂ sensor Firestore access.
FIREBASE_SERVICE_ACCOUNT_PATH	Yes*	Relative path to a Firebase Admin service account JSON file. Used for local development instead of the JSON env var.
NOTEHUB_PROJECT_UID	No	Blues Notehub project UID. Used by the legacy /sensor-data endpoint (Notehub-sourced sensors).
NOTEHUB_ACCESS_TOKEN	No	Blues Notehub bearer token for /sensor-data.
CODETR_API_KEY	No	Co-DETR (camera interoperability) API key. Exposed to the client via /config.

* Exactly one of FIREBASE_SERVICE_ACCOUNT_JSON or FIREBASE_SERVICE_ACCOUNT_PATH must be set for CO₂ sensor and history endpoints to function.

Loading Priority for Firebase Credentials

The server checks credentials in this order:

1. FIREBASE_SERVICE_ACCOUNT_JSON (preferred for cloud deployments — no file path issues)
2. FIREBASE_SERVICE_ACCOUNT_PATH (relative to project root — preferred locally)

If neither is found, CO₂ sensor endpoints return 503 Service Unavailable.

Client-Exposed Variables

The /config endpoint exposes a safe subset to the frontend:

{
  "cesiumIonToken": "...",
  "codetrApiKey": "..."
}

No secret keys (Firebase, TomTom, AirNow, etc.) are ever sent to the client directly — they are always used server-side as proxy credentials.

Example .env

NODE_ENV=development
PORT=3000

CESIUM_ION_TOKEN=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...
TOMTOM_API_KEY=your_tomtom_key_here
AIRNOW_API_KEY=your_airnow_key_here
TRAFFIC_VIEW_API_KEY=your_trafficview_key_here
EM_FIREBASE_API_KEY=AIzaSy...

# Local dev: use file path
FIREBASE_SERVICE_ACCOUNT_PATH=co2_firebase_utils/service_key.json

CODETR_API_KEY=your_codetr_key_here