Simple WordPress XML API

api.php

<?php

$id = intval($_GET['id']);

require_once "../../../wp-load.php";
$args = array( 'numberposts' => 5 );
$lastposts = get_posts( $args );

foreach($lastposts as $post) : setup_postdata($post);
$vimeo = get_post_meta($post->ID, 'vimeo_url', true);
$xml = "
        <data>
            <settings>
                <vimeo>{$vimeo}</vimeo>
            </settings>
        </data>";
echo $xml;
endforeach;