This is the first tool verify any port is online or offline developed by ToTheTech blog and it is so easy to develop with the help of PHP language.

By default to check for any website you can enter the website name example Google.com as shown above picutre and enter port number 80.

Port 80 will give you result online for most of the websites, when port 80 is offline then the website experience down time.

URL : www.tothetech.com/tools/port-check