Curl Command to Repeat URL Request
You could use URL sequence substitution with a dummy query string (if you want to use CURL and save a few keystrokes):
curl http://www.myurl.com/?[1-20]
If you have other query strings in your URL, assign the sequence to a throwaway variable:
curl http://www.myurl.com/?myVar=111&fakeVar=[1-20]
Check out the URL section on the man page: https://curl.haxx.se/docs/manpage.html
You might be interested in Apache Bench tool which is basically used to do simple load testing.
example :
ab -n 500 -c 20 http://www.example.com/
n = total number of request, c = number of concurrent request