tutorial

Monitoring Home Assistant with Vigilmon

Home Assistant is the most popular open-source home automation platform — but when it goes down, your smart home goes dark. Here's how to monitor the web UI, REST API, supervisor health, and automation heartbeats with Vigilmon.

Home Assistant runs the heart of millions of smart homes — lights, locks, thermostats, security cameras, and automation schedules all flow through it. When the instance goes down, everything goes dumb. Vigilmon gives you proactive uptime monitoring for the Home Assistant web interface, REST API endpoints, supervisor health, and SSL certificates, so you know before your family does.

What You'll Set Up

  • HTTP uptime monitor for the Home Assistant web UI (port 8123)
  • REST API health check using a long-lived access token
  • Supervisor health endpoint monitoring
  • SSL certificate expiry alerts for HTTPS setups
  • Heartbeat monitoring for Home Assistant automation schedules

Prerequisites

  • Home Assistant OS, Supervised, Container, or Core installation
  • Home Assistant accessible at http://homeassistant.local:8123 or a custom domain
  • A long-lived access token from your Home Assistant profile
  • A free Vigilmon account

Step 1: Monitor the Home Assistant Web UI

The Home Assistant web interface on port 8123 is the primary entry point for your smart home dashboard. A Vigilmon HTTP monitor confirms the UI is reachable and responding.

  1. Log in to vigilmon.online and click Add Monitor.
  2. Set Type to HTTP / HTTPS.
  3. Enter your Home Assistant URL: http://homeassistant.local:8123 or https://yourdomain.com:8123.
  4. Set Check interval to 1 minute.
  5. Set Expected HTTP status to 200.
  6. Click Save.

If you expose Home Assistant via a reverse proxy (nginx, Caddy, Traefik), use the proxied URL instead of the direct port. The redirect to the login page still returns a 200, so no further configuration is needed.

Step 2: Monitor the REST API with a Long-Lived Access Token

Home Assistant exposes a REST API at /api/ that automation tools and integrations rely on. Monitoring the API health endpoint gives you a richer signal than the UI check alone — the API can fail while the frontend still loads from cache.

Generate a Long-Lived Access Token

  1. Open Home Assistant and click your profile icon (bottom left).
  2. Scroll to Long-Lived Access Tokens and click Create Token.
  3. Name it vigilmon and copy the token — it won't be shown again.

Add the API Monitor in Vigilmon

  1. Click Add Monitor → HTTP / HTTPS.
  2. Enter the URL: http://homeassistant.local:8123/api/
  3. Add a custom request header:
    • Name: Authorization
    • Value: Bearer YOUR_LONG_LIVED_TOKEN
  4. Set Expected HTTP status to 200.
  5. Set Expected response body to contain "message":"API running.".
  6. Set Check interval to 5 minutes.
  7. Click Save.

A successful response looks like:

{"message": "API running."}

If the API returns anything else — or times out — Vigilmon alerts you immediately.

Step 3: Monitor the Supervisor Health API

If you run Home Assistant OS or Supervised, the Supervisor manages add-ons, updates, and system health. The Supervisor exposes a health endpoint you can probe from within the host network.

Add a monitor for the Supervisor health check:

  1. Click Add Monitor → HTTP / HTTPS.
  2. Enter the URL: http://homeassistant.local:8123/api/hassio/supervisor/info
  3. Add the same Authorization header with your long-lived token.
  4. Also add the header X-Hassio-Key with the Supervisor token (found at /etc/environment on the host as SUPERVISOR_TOKEN).
  5. Set Expected HTTP status to 200.
  6. Set Check interval to 5 minutes.
  7. Click Save.

For Container or Core installations without Supervisor, skip this step and rely on the API monitor from Step 2.

Step 4: Monitor the Core State Endpoint

The /api/core/state endpoint reports Home Assistant's running state and is a reliable proxy for overall system health:

  1. Click Add Monitor → HTTP / HTTPS.
  2. Enter the URL: http://homeassistant.local:8123/api/config
  3. Add the Authorization: Bearer YOUR_TOKEN header.
  4. Set Expected HTTP status to 200.
  5. Set Expected response body to contain "state":"RUNNING".
  6. Click Save.

This catches situations where Home Assistant is technically reachable but stuck in a loading or error state after a bad update or configuration change.

Step 5: SSL Certificate Alerts for HTTPS Setups

Many Home Assistant setups use Let's Encrypt certificates via the Duck DNS or NGINX Proxy Manager add-ons, or through Nabu Casa. Certificate expiry can break remote access silently.

Enable SSL monitoring on your HTTPS monitor:

  1. Open the HTTP / HTTPS monitor created in Step 1 (use your HTTPS URL).
  2. Enable Monitor SSL certificate under the SSL section.
  3. Set Alert when certificate expires in less than 21 days.
  4. Click Save.

For Nabu Casa remote access, the certificate is managed by Home Assistant Cloud — but local certificates for homeassistant.local or custom domains still need monitoring.

Step 6: Heartbeat Monitoring for Automation Schedules

Home Assistant runs automation scripts on schedules — morning routines, evening modes, security checks. If the automation engine stalls or the instance restarts mid-schedule, the automations silently stop firing. A Vigilmon heartbeat catches this.

  1. In Vigilmon, click Add Monitor → Cron Heartbeat.
  2. Set the expected ping interval to match your most critical automation (e.g. 60 minutes for an hourly script).
  3. Copy the heartbeat URL (e.g. https://vigilmon.online/heartbeat/abc123).
  4. In Home Assistant, add a rest_command to your configuration.yaml:
rest_command:
  vigilmon_heartbeat:
    url: "https://vigilmon.online/heartbeat/abc123"
    method: GET
  1. Then call it from your automation:
automation:
  - alias: "Hourly Health Ping"
    trigger:
      - platform: time_pattern
        minutes: "/60"
    action:
      - service: rest_command.vigilmon_heartbeat

If the automation engine stalls or Home Assistant crashes, the heartbeat stops, and Vigilmon alerts you after the expected interval.

Step 7: Configure Alert Channels

  1. Go to Alert Channels in Vigilmon and add email, Slack, or a webhook (e.g. to trigger a Home Assistant notification via the API when an external monitor itself goes down).
  2. Set Consecutive failures before alert to 2 on the UI monitor — Home Assistant occasionally takes 10–20 seconds to respond during startup.
  3. Use Maintenance windows in Vigilmon to suppress alerts during planned updates:
curl -X POST https://vigilmon.online/api/maintenance \
  -H "Authorization: Bearer YOUR_VIGILMON_API_KEY" \
  -d '{"monitor_id": "abc123", "duration_minutes": 10}'

Summary

| Monitor | Target | What It Catches | |---|---|---| | Web UI | http://homeassistant.local:8123 | Frontend down, instance crashed | | REST API | /api/ with Bearer token | API failure, auth broken | | Core state | /api/config | HA stuck in loading/error state | | Supervisor | /api/hassio/supervisor/info | Supervisor crash, add-on failure | | SSL certificate | HTTPS domain | Certificate expiry, renewal failure | | Cron heartbeat | Heartbeat URL | Automation engine stall, missed schedule |

Home Assistant is your smart home's nervous system — when it goes down, every device goes with it. With Vigilmon watching the web UI, REST API, supervisor health, and automation heartbeats, you'll know the moment something goes wrong and can restore your home automation before it impacts daily life.

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