NL-Alert (Nearby)

A custom Home Assistant integration that monitors NL-Alert messages for the Netherlands and determines whether they are near or affecting your configured zone (e.g. zone.home).

The integration fetches official NL-Alert data, calculates accurate distances to alert areas (using polygon-edge math), and exposes multiple sensors for automation and dashboards.

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✨ Features

• 🇳🇱 Uses the official NL-Alert public API
• 📍 Configurable zone (default: zone.home)
• 📏 Configurable radius (km)
• 🗺️ Accurate distance calculation:
  • Distance to polygon edges
  • 0 km if your zone is inside the alert area
• 🧠 Fully configurable via the Home Assistant UI (no YAML)
• 🔄 Automatic updates on a configurable interval
• 🧾 Exposes alert text, timing, and distance
• 🕘 Tracks the most recent inactive NL-Alert
• ⚙️ Option to track last inactive alert:
  • Only within your zone/radius or
  • Anywhere in the Netherlands
• 🌍 English and Dutch translations included
• 🧩 HACS compatible

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🧩 Sensors Created

sensor.nl_alert_nearby

State

• Number of active NL-Alerts within your configured radius

Attributes

• alerts: list of matching alerts
  • id
  • message
  • start_at
  • stop_at
  • distance_km

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sensor.nl_alert_nearby_closest_distance

State

• Distance (km) to the closest active NL-Alert area

Meaning

• 0.0 km → your zone is inside the alert area
• > 0 km → alert nearby
• unknown → no active alerts within radius

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sensor.nl_alert_nearby_last_inactive

Tracks the most recent NL-Alert that is no longer active from the current API response.

State

• Timestamp when the last inactive alert stopped (shown in relative time like "4 days ago")

Attributes

• id
• message
• start_at
• stop_at
• distance_km

Note: This sensor shows the latest inactive alert from the API at the time of each update. It does not persist historical data across restarts.

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⚙️ Configuration (UI)

All configuration is done via:

Settings → Devices & Services → Add Integration → NL-Alert (Nearby)

Initial setup options

• Name (default: NL-Alert (Nearby))
• Zone (default: zone.home)
• Radius (km) (default: 25.0)
• Update interval (seconds) (default: 300)
• Last inactive alert scope
  • Only within your zone/radius (default)
  • Anywhere in the Netherlands

Changing configuration later

• To change zone: Use the Reconfigure option (three dots menu → Reconfigure)
• To change radius, interval, or scope: Use the Options menu (three dots menu → Configure)

Note: Each zone can only be configured once. To monitor multiple zones, add multiple instances of the integration.

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🛠️ Installation

Option 1: Install via HACS (recommended)

1. Open HACS
2. Go to Integrations
3. Click ⋮ → Custom repositories
4. Add:
   • Repository: https://github.com/Diondk/nlalert_radius
   • Category: Integration
5. Search for NL-Alert (Nearby)
6. Install
7. Restart Home Assistant
8. Add the integration via Devices & Services

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Option 2: Manual installation

1. Download or clone this repository
2. Copy the folder:

   custom_components/nlalert_radius
   

   to your Home Assistant custom_components directory
3. Restart Home Assistant
4. Add the integration via Settings → Devices & Services → Add Integration

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📝 Example Automations

Send notification when alert becomes active nearby

This automation triggers when any NL-Alert appears within your configured radius and sends a notification with the alert message and distance.

Example: If there's a fire in Roermond and you're 40 km away with a 70 km radius configured, you'll receive a notification like: "Brand in Roermond - Distance: 40 km"

automation:
  - alias: "NL-Alert Nearby Notification"
    trigger:
      - platform: state
        entity_id: sensor.nl_alert_nearby
    condition:
      - condition: numeric_state
        entity_id: sensor.nl_alert_nearby
        above: 0
    action:
      - service: notify.mobile_app
        data:
          title: "🚨 NL-Alert Nearby"
          message: >
            {{ state_attr('sensor.nl_alert_nearby', 'alerts')[0].message }}
            Distance: {{ state_attr('sensor.nl_alert_nearby', 'alerts')[0].distance_km }} km

Alert when zone is inside alert area

This automation triggers when your zone is directly inside an active alert area (distance = 0 km), meaning you are in the affected zone and should take immediate action.

Example: If an NL-Alert is issued for your city and your home location is within the alert polygon, you'll receive: "Your location is affected!" with distance showing 0.0 km.

automation:
  - alias: "NL-Alert Zone Inside Alert Area"
    trigger:
      - platform: numeric_state
        entity_id: sensor.nl_alert_nearby_closest_distance
        below: 0.1
    action:
      - service: notify.mobile_app
        data:
          title: "⚠️ NL-Alert - Your location is affected!"
          message: >
            {{ state_attr('sensor.nl_alert_nearby', 'alerts')[0].message }}

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🔧 Troubleshooting

Integration doesn't load

• Check that you've restarted Home Assistant after installation
• Check the Home Assistant logs for errors related to nlalert_radius

No alerts showing up

• Verify your zone entity has valid coordinates
• Check if there are any active NL-Alerts at https://api.public-warning.app/api/v1/providers/nl-alert/alerts
• Verify your radius is large enough
• Check the integration logs for API errors

"Zone already configured" error

• Each zone can only be configured once
• To change settings for an existing zone, use the Options or Reconfigure menu
• To monitor a different zone, delete the existing integration first or use a different zone entity

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📡 Data Source

This integration uses the Public Warning App API which provides official NL-Alert data for the Netherlands.

API Endpoint: https://api.public-warning.app/api/v1/providers/nl-alert/alerts

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📄 License

This project is licensed under the MIT License.

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🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

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⭐ Support

If you find this integration useful, please consider giving it a star on GitHub!