vegancheck.me/script.php

<?php
// Vegan: https://world.openfoodfacts.org/api/v0/product/4251105509585.json
// Vegan uknown: https://world.openfoodfacts.org/api/v0/product/4008638170726.json
// Not vegan: 5000159404259

$barcode = $_GET['barcode'];

$data = file_get_contents('https://world.openfoodfacts.org/api/v0/product/'.$barcode.'.json');

$product = json_decode($data);

$array = $product->product->ingredients_analysis_tags;
$name = $product->product->product_name;

if (in_array("en:non-vegan", $array)) {
    echo '"'.$name.'" is most likely not Vegan';
}
elseif (in_array("en:vegan-status-unknown", $array)) {
    echo  'We are not sure if "'.$name.'" is vegan or not.';
}
elseif (in_array("en:vegan", $array)) {
	echo  '"'.$name.'" is Vegan!';
}
else {
	echo "This product is not in our database yet.";
}
?>