From cURL JSON to PHP variable

Question

I have JSON from cURL

<?php
$url = "https://example.com";

$curl = curl_init($url);
curl_setopt($curl, CURLOPT_URL, $url);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);

$headers = array(
    "Content-Type: application/json",
    "Authorization:xxxxxxxxxxxxx",
);
curl_setopt($curl, CURLOPT_HTTPHEADER, $headers);
//for debug only!
//curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);
//curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);

$resp = curl_exec($curl);
//var_dump($resp);

$leads = json_decode($resp);

print_r($leads);
curl_close($curl);
?>

Output is

stdClass Object 
([status] => 200
[data] => Array( [0] => stdClass Object (
            [firstname] => Jon 
            [lastname] => Jonson
            [email] => jon@jonson.com
) ) ) 

I tried with foreach to get firstname, lastname, email but without success. Also tried with $leads = json_decode($resp, true); but only can get the first array.

How can I get it for each array?