It's really simple to use this API, you must use it like : https://api.greensnow.co/8.8.8.8
And you can retrieve a JSON with the blockage flag and more (first_report, last_report, nb_attack, country, reverse)
More information : https://greensnow.co/contact

Quick example of use :
=========================
< ?php
$ip = '78.110.164.209';
$ctx=stream_context_create(array('http'=>array('timeout' => 1)));
$api = @json_decode(file_get_contents('http://api.greensnow.co/'.$ip,false,$ctx));

if(isset($api))
{
    echo 'Blocked :'. $api->blocked.'<br>';
    echo 'First Report :'. $api->first_report.'<br>';
    echo 'Last Report :'. $api->nb_attack.'<br>';
    echo 'Nb Attack :'. $api->nb_attack.'<br>';
    echo 'Country :'. $api->country.'<br>';
    echo 'Reverse :'. $api->reverse.'<br>';
}