I'm on IBM AIX 7.1 where cURL and wget are not available. Also, I'm not in a position to install either.
Are there alternatives that would be available that would enable remote API calls using GET/POST?
Since perl is installed by default in AIX, you could use the HTTP and LWP modules; an example, from https://metacpan.org/pod/distribution/libwww-perl/lwpcook.pod#POST, is:
use HTTP::Request::Common qw(POST); use LWP::UserAgent; $ua = LWP::UserAgent->new; my $req = POST 'https://rt.cpan.org/Public/Dist/Display.html', [ Status => 'Active', Name => 'libwww-perl' ]; print $ua->request($req)->as_string;