Pingdom
Commercial
Pingdom helps you give your customers the best possible web experience by offering a Powerful Web Performance Monitoring Solution.
Gtmetrix
Free
Gtmetrix is a website speed analyzer.
PageSpeed Insights
Open Source
Uptrends
Commercial
Uptrends helps you monitor your website uptime, so you will get an alert whenever your websites goes down.
Compare DareBoost with alternatives
Compare PageSpeed Insights and DareBoost and decide which is most suitable for you.