SE Ranking - All-in-One cloud-based SEO software for agencies, marketing teams and webmasters
Pingdom - With website monitoring from Pingdom you will be the first to know when your website is down. No installation required. 30-day free trial.
Ahrefs - Ahrefs is a toolset for SEO and marketing. We have tools for backlink research, organic traffic research, keyword research, content marketing & more. Give Ahrefs a try!
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
Moz - Backed by industry-leading data and the largest community of SEOs on the planet, Moz builds tools that make inbound marketing easy.
Better Uptime - We call you when your website goes down