Site Monitoring

https://downdetector.com

The site shows the load schedule of the leading sites, which shows declines in attendance. So you can find out when and where there were failures.

Collects reports on the state from a number of sources. By analyzing these data in real-time, the system is able to automatically detect failures and service outages at a very early stage. One of the sources that are analyzed is the reports on Twitter.

The system determines failures when the number of reports makes a significant jump in relation to the basic indicator. Reports for each company are tracked on a separate page and publish a brief update after the problem is detected. Previous reports are available in the archive by reference or in the Problem Review.

https://www.similarweb.com

Website statistics on any domain.

https://uptimerobot.com

Site validation service.

Several types of site availability check: simple server response check, validate download.

Monitor 50 different sites for free.
Statistics look at mail or by SMS.

https://ionos.com/tools/website-checker

The servise analyzes your website to see how well equipped it is for online success, and gives you tips on how you can improve it. You can implement many of these tips immediately yourself, and 1&1 offers additional products to help you take advantage of the full range of advice.