Free Website Status Monitoring Program

1. uptimerobot
Free accounts can submit 50 websites for monitoring. You Can Get Notifications via email, rss, SMS, and Twitter. The last two types are invalid for domestic users. There are two notification statuses: down and up. Check your website every 5 minutes
Registered address: http://www.uptimerobot.com/

2. service uptime
One free account can only submit one website for monitoring. The monitoring interval is 30 minutes. This website can monitor both http and ftp statuses.
Get the website down or up information by email. This website has many monitoring sites.
Registered address: http://www.serviceuptime.com/

3. Monitoring
Cloudmonitor supports various deployment types of websites, including virtual hosts, hosted hosts, rented hosts, virtual hosts (VPS), and Cloud Computing platforms (Cloud Computing ).
Cloudmonitor uses various network protocols for site monitoring, including HTTP, Ping, DNS, FTP, SMTP, POP, IMAP, and TCP.
Cloudmonitor uses the SNMP protocol to monitor server performance and capacity, and supports various servers, including Linux, Windows, BSD, Mac, Solaris, And AIX.
Registered address: http://www.jiankongbao.com/