curl 'https://wifi.provider.ltd/path-to-script.php' \
-XPOST \
-H 'Content-Type: application/x-www-form-urlencoded; charset=UTF-8' \
-H 'Origin: https://wifi.provider.ltd' \
-H 'Host: wifi.provider.ltd' \
-H 'Accept: application/json, text/javascript, */*; q=0.01' \
-H 'Connection: keep-alive' \
-H 'Accept-Encoding: br, gzip, deflate' \
-H 'Accept-Language: en-us' \
-H 'DNT: 1' \
-H 'Cookie: PHPSESSID=ld9tadtaas0cvjvmhvjjsaobi1' \
-H 'User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_5) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/11.1.1 Safari/605.1.15' \
-H 'Referer: https://wifi.provider.ltd/' \
-H 'Content-Length: 37' \
-H 'X-Requested-With: XMLHttpRequest' \
--data 'username=someuser&password=somepass'