use JSON;

my %mail = (
  fromName    => 'Alice',
  fromEmail   => 'alice@example.com',
  to          => 'bob@example.net',
  cc          => 'carol@example.net',
  bcc         => 'dave@example.org',
  subject     => 'Test message',
  messageHtml => '<p>Test</p>',
  messageText => "Test\n",
);

open my $sm, '|php sendMail-cli.php' or die 'could not open pipe to send mail';
print {$sm} encode_json(\%mail);
close $sm;