$json = '{"UID":"71","name":"Семантическое ядро","lang":"ru","short_name":"Семантическое ядро","h1":"Семантическое ядро","seo":"keywords","parent":"17","max_days":30,"is_package_free_price":"1","max_photo_count":"3","order_3_day":"31","twin_category_id":"188","portfolio_type":"none","portfolio_avaliable":"0","allow_mirror":"0","custom_offer":"0","collage_image":"keywords.jpg","sort_index":"2","mobile_description":"","kwork_count":"764","images_update_time":null,"deleted_at":null,"month_revenue":"454400.00","portfolio_image_size":"0","id":"71","image_name":"keywords","resolution":{"width":660,"height":440},"attributes":{"3799":{"id":3799,"category_id":71,"title":"С нуля","visible":"1"},"3800":{"id":3800,"category_id":71,"title":"По сайту","visible":"1"},"186454":{"id":186454,"category_id":71,"title":"Готовое ядро","visible":"1"}}},';
$json = substr($json, 0, -1);
$arr = json_decode($json, true);
echo '<pre>' . print_r($arr, true);