For loop with Curl request - PHP

Question

I'm checking against a list of address books (outputted as checkboxes) to see which books the user has selected. For the selected ones I'm adding them to an ESP via their API using curl.

I have the following code which is achieving the desired result, however it's causing a pretty slow page load, I think this is because I'm looping through a large chunk of curl requests up to 15 times (once for each address book) and wondered if someone could help me tidy this up?

$aBook = $_POST['addressBooks'];
$N = count($aBook);

    for($i=0; $i < $N; $i++)
    {
      $content = [
            'email' => $_POST['email']
        ];
        global $baseUrl, $apiUsername, $apiPassword;
        $url = $baseUrl . '/v2/address-books/' . $aBook[$i] . '/contacts';
        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt(
            $ch, CURLOPT_HTTPHEADER, array('Accept: application/json',
                                           'Content-Type: application/json')
        );
        curl_setopt($ch, CURLAUTH_BASIC, CURLAUTH_DIGEST);
        curl_setopt(
            $ch, CURLOPT_USERPWD,
            $apiUsername . ':' . $apiPassword
        );
        curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "POST");
        curl_setopt($ch, CURLOPT_POSTFIELDS,json_encode($content));

        $response = json_decode(curl_exec($ch));

    }

Answer 1

Since $abook is an array, why not serialize it and send just one curl request and do your backend processing once. If firing multiple queries using transactions would be good.