The Web Requests mod adds one command, /request, which contains the two sub-commands get and post
/request get <URL> <headers>
example:
/request get https://example.com "foo:bar:::hello:world"
/request post <URL> <headers> <body>
A string that should be contained in quotation marks ("")
headers are formatted like so: key1:value1:::key2:value2, triple colons separate the headers
the body is a string also in quotation marks ("")