基于 列表成员实例文档，最简单的方法是使用 PUT 请求，根据文档要么添加新的列表成员或更新如果电子邮件已存在于列表中，则为成员".

Based on the List Members Instance docs, the easiest way is to use a PUT request which according to the docs either "adds a new list member or updates the member if the email already exists on the list".

此外，apikey 绝对不是 json 架构的一部分 并且没有必要将它包含在您的 json 请求中.

Furthermore apikey is definitely not part of the json schema and there's no point in including it in your json request.

此外，如@TooMuchPete 的评论所述，您可以使用 CURLOPT_USERPWD 进行基本的 http 身份验证，如下所示.

Also, as noted in @TooMuchPete's comment, you can use CURLOPT_USERPWD for basic http auth as illustrated in below.

我正在使用以下函数来添加和更新列表成员.根据您的列表参数，您可能需要包含一组略有不同的 merge_fields.

I'm using the following function to add and update list members. You may need to include a slightly different set of merge_fields depending on your list parameters.

$data = [
    'email'     => 'johndoe@example.com',
    'status'    => 'subscribed',
    'firstname' => 'john',
    'lastname'  => 'doe'
];

syncMailchimp($data);

function syncMailchimp($data) {
    $apiKey = 'your api key';
    $listId = 'your list id';

    $memberId = md5(strtolower($data['email']));
    $dataCenter = substr($apiKey,strpos($apiKey,'-')+1);
    $url = 'https://' . $dataCenter . '.api.mailchimp.com/3.0/lists/' . $listId . '/members/' . $memberId;

    $json = json_encode([
        'email_address' => $data['email'],
        'status'        => $data['status'], // "subscribed","unsubscribed","cleaned","pending"
        'merge_fields'  => [
            'FNAME'     => $data['firstname'],
            'LNAME'     => $data['lastname']
        ]
    ]);

    $ch = curl_init($url);

    curl_setopt($ch, CURLOPT_USERPWD, 'user:' . $apiKey);
    curl_setopt($ch, CURLOPT_HTTPHEADER, ['Content-Type: application/json']);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_TIMEOUT, 10);
    curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'PUT');
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $json);                                                                                                                 

    $result = curl_exec($ch);
    $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    curl_close($ch);

    return $httpCode;
}