Uptime Kuma is a self-hosted uptime monitor with a clean dashboard, lots of check types (HTTP/TCP/Ping/DNS/WebSocket/etc.), and tons of notification integrations. It’s blown up in the self-hosting world (82.7k GitHub stars, 7.4k forks), mostly because it fixes the “I just want alerts + a status page without paying UptimeRobot-like limits” problem and is dead simple to try in minutes.