How to read JSON Data in PHP Without Knowing the Keys Beforehand

I have following JSON response in PHP

{
    "tlds": {
        ".art": {
            "register": "16.99",
            "transfer": "16.99",
            "renew": "16.99",
            "transfer_requires_epp_code": true,
            "id_protection_supported": true
        },
        ".icu": {
            "register": "12.99",
            "transfer": "12.99",
            "renew": "12.99",
            "transfer_requires_epp_code": true,
            "id_protection_supported": true
        },
        ".xyz": {
            "register": "2.99",
            "transfer": "13.99",
            "renew": "13.99",
            "transfer_requires_epp_code": true,
            "id_protection_supported": true
        },
        ".cyou": {
            "register": "12.99",
            "transfer": "12.99",
            "renew": "12.99",
            "transfer_requires_epp_code": true,
            "id_protection_supported": true
        },
        ".fr": {
            "register": "12.99",
            "transfer": "12.99",
            "renew": "12.99",
            "transfer_requires_epp_code": true,
            "id_protection_supported": false
        },
        ".be": {
            "register": "7.99",
            "transfer": "7.99",
            "renew": "12.99",
            "transfer_requires_epp_code": false,
            "id_protection_supported": false
        },
        ".ca": {
            "register": "8.99",
            "transfer": "8.99",
            "renew": "9.99",
            "transfer_requires_epp_code": true,
            "id_protection_supported": false
        },
        ".ch": {
            "register": "8.99",
            "transfer": null,
            "renew": "13.99",
            "transfer_requires_epp_code": true,
            "id_protection_supported": true
        }
    },
    "currency_code": "USD",
    "message": "Successfully retrieved prices",
    "fgt_id": "xxxxxxxxxxxxxxxxx"
}

And following code to echo in php the result

$response = curl_exec($curl);
$decoded_json = json_decode($response, true);
echo "<table><tr><td>Extension</td><td>Register</td><td>Transfer</td><td>Renew</td></tr>";
foreach ($decoded_json['tlds'] as $key => $value) {
    echo "<tr><td>".$decoded_json['tlds']."</td><td>".$value['register']."</td><td>".$value['transfer']."</td><td>".$value['renew']."</td><tr>";
}
echo "</table>";

But that doesn’t work. It breaks the page. I only mentionned 8 domainname extensions, but there are much more in the real response. This means we have to consider the domainname extensions as unknown keys. How to echo the response data taking into accout that the tlds has many rows with the first key unknown?