Upcheck

Upcheck monitors every website you own for uptime, SSL certificate expiry, DNS changes, and domain renewal. It alerts your team via email, Slack, Discord, Teams, or webhook before small issues escalate into outages. Upcheck checks your sites every twelve hours and allows you to set notification thresholds of 30, 14, and 7 days for each site.

It requires no agent, no DNS changes, and no code on your side, making it easy to integrate into your workflow.