A comprehensive cron script that monitors website availability with intelligent alerting and historical tracking.

• Monitors multiple websites concurrently for better performance
• 10-second timeout with proper AbortController implementation
• Detailed response time tracking
• HTTP status code monitoring
• Comprehensive error categorization

• Failure Threshold: Only alerts after 2 consecutive failures (reduces false positives)
• Notification Cooldown: 30-minute cooldown between alerts for the same site
• Recovery Notifications: Alerts when sites come back online
• Detailed Error Reports: Includes status codes, error messages, response times, and failure counts

• Persistent storage using Val Town blob storage
• Tracks consecutive failure counts
• Maintains last notification timestamps
• Records site status history

• Proper timeout handling with AbortController
• Detailed error categorization (timeouts, HTTP errors, network errors)
• Graceful handling of storage failures

• https://esm.town/v/std/email - Email notifications
• https://esm.town/v/std/blob - Persistent storage

const TIMEOUT_MS = 10000; // 10 seconds
const FAILURE_THRESHOLD = 2; // Alert after 2 consecutive failures
const NOTIFICATION_COOLDOWN_MS = 30 * 60 * 1000; // 30 minutes between notifications

1. Fork this val
2. Update SITES_TO_MONITOR array with your websites
3. Set a cron schedule (recommended: every 5-10 minutes)
4. The script will automatically start tracking and alerting

A site is considered "down" if:

• No response within 10 seconds (timeout)
• Returns a non-2xx HTTP status code
• Network/connection errors occur
• DNS resolution fails

• Subject: 🚨 X site(s) down
• Body: Detailed breakdown including:
  • Site URL
  • HTTP status code
  • Error message
  • Response time
  • Consecutive failure count

• Subject: ✅ X site(s) recovered
• Body: List of recovered sites

When both downtimes and recoveries occur, both are included in a single email.

The script maintains persistent state in Val Town blob storage:

• uptime_history: JSON object tracking each site's status history
• Includes last status, consecutive failures, last notification time, etc.

WTFPL