A serverless monitoring solution for your home server with real-time push notifications.

• Web UI: https://halffullheartbeat.val.run
• Heartbeat Endpoint: POST https://halffullheartbeat.val.run/heartbeat

1. Go to https://www.val.town/v/halffullheart/heartbeat/generate-vapid-keys
2. Click "Run" to generate your VAPID keys
3. Copy the keys from the output

1. Go to your val settings: https://www.val.town/v/halffullheart/heartbeat
2. Click "Environment Variables"
3. Add these three variables:
   • VAPID_PUBLIC_KEY - from step 1
   • VAPID_PRIVATE_KEY - from step 1
   • VAPID_EMAIL - your email (e.g., mailto:you@example.com)

Add a cron job or scheduled task on your home server to ping the heartbeat endpoint every 15 minutes:

Linux/Mac (crontab):

# Add to crontab (run: crontab -e)
*/15 * * * * curl -X POST https://halffullheartbeat.val.run/heartbeat

Windows (Task Scheduler PowerShell):

# Run every 15 minutes
$action = New-ScheduledTaskAction -Execute 'powershell.exe' -Argument '-Command "Invoke-WebRequest -Uri https://halffullheartbeat.val.run/heartbeat -Method POST"'
$trigger = New-ScheduledTaskTrigger -Once -At (Get-Date) -RepetitionInterval (New-TimeSpan -Minutes 15)
Register-ScheduledTask -TaskName "ServerHeartbeat" -Action $action -Trigger $trigger

Docker (if your server runs Docker):

# Run this container on your server
docker run -d --name heartbeat --restart unless-stopped \
  alpine/curl:latest sh -c \
  "while true; do curl -X POST https://halffullheartbeat.val.run/heartbeat; sleep 900; done"

Simple Bash Script:

#!/bin/bash
# Save as heartbeat.sh and run: ./heartbeat.sh &

while true; do
  curl -X POST https://halffullheartbeat.val.run/heartbeat
  sleep 900  # 15 minutes
done

1. Open the web UI: https://halffullheartbeat.val.run
2. Click "Enable Notifications"
3. Grant notification permissions when prompted

1. Your Server: Sends a heartbeat every 15 minutes to the /heartbeat endpoint
2. Monitor: Checks every 15 minutes if a heartbeat was received in the last hour
3. Notifications: If no heartbeat for 1+ hour, sends push notifications to all subscribers
4. Web UI: Real-time status display that updates every 30 seconds

Your server calls this endpoint every 15 minutes.

Response:

{
  "success": true,
  "timestamp": 1234567890
}

Get current server status.

Response:

{
  "lastHeartbeat": 1234567890,
  "isOnline": true,
  "minutesSince": 5,
  "currentTime": 1234567890
}

Subscribe to push notifications (called automatically by web UI).

• main.ts: HTTP endpoint with web UI (PWA)
• monitor.ts: Interval function (runs every 15 minutes)
• SQLite Database: Stores heartbeats and notification subscriptions
• Web Push: VAPID-based push notifications

heartbeats table:

• id - Auto-increment primary key
• timestamp - Unix timestamp in milliseconds

subscriptions table:

• id - Auto-increment primary key
• endpoint - Push notification endpoint (unique)
• p256dh - Public key for encryption
• auth - Authentication secret
• created_at - Subscription timestamp

• ✅ Real-time server status monitoring
• ✅ PWA (Progressive Web App) installable on mobile
• ✅ Push notifications when server goes down
• ✅ Beautiful, responsive UI
• ✅ Automatic cleanup of invalid subscriptions
• ✅ CORS-enabled API
• ✅ Service Worker for offline support

• Environment variables for sensitive keys
• VAPID keys for authenticated push notifications
• CORS headers for API access
• Unique subscription endpoints per device

• Server is considered "down" after 1 hour without heartbeat
• Monitor runs every 15 minutes (configurable in monitor.ts)
• Notifications sent to all active subscribers
• Invalid subscriptions automatically removed
• SQLite database scoped to this val

No notifications?

• Check that VAPID environment variables are set
• Ensure you granted notification permissions
• Check monitor.ts logs for errors

Server showing offline?

• Verify your server's cron job is running
• Check that the heartbeat endpoint is reachable
• Look at the heartbeat timestamps in the database

Test the heartbeat:

curl -X POST https://halffullheartbeat.val.run/heartbeat

For issues or questions, check the Val Town documentation: https://docs.val.town