use LWP::UserAgent;
use JSON;

my $ua = LWP::UserAgent->new;
my $server_endpoint = "http://api.someserver.com/v1/";
my $req = HTTP::Request->new(POST => $server_endpoint);

$req->authorization_basic('myusername', 'mypassword');

my $post_data = {
	parm1 => $valueasscalar,
	parm2 => \1, # this gives you a proper JSON 'true'
};
my $json = encode_json($post_data);

$req->content_type('application/json');
$req->content($json);

my $resp = $ua->request($req);
# etc