Looking for a free self-hosted uptime monitoring solution

The most robust approach is to run a dedicated open-source monitoring tool on your VPS, with Uptime Kuma being the current best-in-class solution for your needs. While a simple bash script with cron can work, it lacks a dashboard, historical data, and can be fragile; a purpose-built tool provides a centralized interface and more reliable alerting mechanisms. Uptime Kuma is lightweight, easy to install via Docker, and includes features like multiple notification methods (email, Telegram, Discord) and status pages.

To deploy Uptime Kuma, ensure Docker is installed and run:

docker run -d --restart=always -p 3001:3001 -v uptime-kuma:/app/data --name uptime-kuma louislam/uptime-kuma:1

After running this, access the web interface at `http://your-vps-ip:3001` to complete the setup, add your websites (monitors), and configure email alerts via SMTP. The underlying concept is active health checking, where the tool periodically sends HTTP requests to your endpoints and triggers alerts based on the response code and latency. For a script-based alternative, this cron job checks a site and sends an email alert on failure, though it requires a local mail server like Postfix to be configured:

*/5 * * * * curl -f -s -o /dev/null -w "%{http_code}" https://yoursite.com || echo "Site is down" | mail -s "Alert: Site Down" your@email.com