WebGazer - Monitor your website's availability with WebGazer, review its performance and get instant notifications when your website goes down. No installation required and free plan available.
Hexometer™ Website Hygiene Attendant - Website audit and monitoring platform based on AI technology
Oh Dear! - Website monitoring, without the hassle
Spike - Spike solves businesses' communication chaos by bringing together email, team chat, collaborative docs, and meetings, into one feed.
updown.io - updown.io is a HTTP(S)/TCP/ICMP monitoring service which checks periodically the URL you want and reports back any anomaly.
Suprvise - Know instantly when your sites are down.