Port Monitor is an easy tool that does website and server monitoring 24/7 every 60 seconds for free.

UptimeRobot is a free website uptime monitoring service.

StatusCake delivers accurate global website monitoring for tens of thousands of customers.

HappyApps is an online app uptime monitoring platform.

Wachete is a website content monitoring platform.

Uptrends helps you monitor your website uptime, so you will get an alert whenever your websites goes down.

AppBeat is reliable website monitoring service that alerts you when there is a downtime or failure. It also measures performance and provides functional tests…

Pingdom helps you give your customers the best possible web experience by offering a Powerful Web Performance Monitoring Solution.

Down For Everyone Or Just Me enables users to check whether a specific website is inaccessible for everyone or only for them.

Monitis is a web performance monitoring platform.

Pingoscope is a website monitoring site.