How to convert and use JSON data from a remote WordPress server?

On server B:

$result = wp_remote_post('http://serverA.com/?api=json', array(
    'method'      => 'POST',
    'redirection' => 1,
    'httpversion' => '1.0',
    'blocking'    => true,
    'headers'     => array(),
    'body'        => array(),
    'cookies'     => array()
));
if ( is_wp_error( $result ) ) {
    return 'bad connection!';
}
$json = $result['body'];
$posts = json_decode($json);

Now you have $posts as usual php array. var_dump($posts) will look like:

array(2) {
  [0]=>
  object(stdClass)#7918 (4) {
    ["id"]=>
    int(19)
    ["title"]=>
    string(18) "Early bird tickets"
    ["content"]=>
    string(12) "that is good"
    ["imageurl"]=>
    string(65) "http://localhost/PRACTISE/wp/wp-content/uploads/2016/10/news2.jpg"
  }
  [1]=>
  object(stdClass)#7919 (4) {
    ["id"]=>
    int(95)
    ["title"]=>
    string(18) "See you next year!"
    ["content"]=>
    string(11) "Lorem ipsum"
    ["imageurl"]=>
    string(73) "http://localhost/PRACTISE/wp/wp-content/uploads/2016/11/tak_for_i_aar.jpg"
  }
}