
Moonitor
Uptime monitoring for a one-off price on AppSumo: 20 monitors at 60-second checks, SSL checks, all alert channels and branded status pages.

Updown.io
Pay-as-you-go website monitoring with no subscription: buy credits, check every 15 seconds to every hour, and get SSL and domain expiry alerts.

Site24x7
Free forever website monitoring for 50 sites at 5-minute checks, with SSL certificate expiry checks, a public status page and uptime reports.

Hyperping
Free uptime and SSL monitoring for 20 checks from 18 regions, with email, Slack and Teams alerts and a basic status page. No card needed.

HetrixTools
Free uptime monitoring for 15 sites at 1-minute checks, with SSL expiry, domain expiry and nameserver-change alerts plus a public status page.