📶 Uptime Kuma.

• Convenient open source tool for monitoring network resources. Can send alerts to you in Telegram, Discord, Gotify, Slack, Pushover, Email and a bunch of other different services. Allows you to monitor the expiration date of SSL certificates, sites via HTTP, DNS records, open TCP ports, the status of Docker containers, SQL servers and a bunch of other different things: https://github.com/louislam/uptime-kuma

• On the downside, there is a lack of monitoring of server parameters (disk space, load).

• You can, of course, use Zabbix, but for many it will be a heavyweight and redundant solution.