I'm trying to format a response from an api but i keep getting Warning: Undefined array key "timestamp"

Here is the code

namespace App\Controller;

use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\Routing\Annotation\Route;
use Symfony\Component\HttpClient\HttpClient;

class ApiController extends AbstractController
{
       /**
     * @Route("/api/fetch-data", name="api_fetch_data")
     */
    public function fetchData(): Response
    {
        // Fetch data from API
        $client = HttpClient::create();
        $response = $client->request('GET', 'https://anyapi.io/api/v1/exchange/rates?apiKey=960k8dih5kouba5h0luhu8aghl7nnc4no8q6ung7lcvgj64bm5ic2i8');
        $data = $response->getContent();
       // $data = json_decode($response->getContent(), true);

        // Process data
        $data = json_decode($data, true);

        // ...
       // Access the data in the PHP object
       $timestamp = $data['timestamp'];
       $base_currency = $data['source'];
       $rates = $data['quotes'];
       
       // Print the formatted data
       echo "Timestamp: " . date('Y-m-d H:i:s', $timestamp) . "\n";
       echo "Base currency: " . $base_currency . "\n";
       foreach ($rates as $currency => $rate) {
           echo $currency . ": " . $rate . "\n";
       }
        // Return response
        return $this->json([
            'data' => $data,
        ]);
    }
    
}

I see a "lastUpdate" but no "timestamp", just change the name in your code. Same for "source" => base and "quotes" => rates.

The output:

*Array
(
    [lastUpdate] => 1678320000
    [base] => EUR
    [rates] => Array
        (
            [EUR] => 1
            [USD] => 1.0554

        )

)*