How to send email with file attachment using Mailgun API

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1

I’m trying to send emails with file attachments through the Mailgun service but running into problems. The emails are being delivered successfully but the attachments are not included. When I try to use a file path, it just shows the path as text instead of attaching the actual file.

Here’s the code I’m currently using:

<?php
$api_key = 'key-8bx9ynkp52hd8fds6gc484tgvkxueol1';
$api_version = 'api.mailgun.net/v3/';
$domain_name = "example.mailgun.org";
$sender_email = "[email protected]";
$reply_address = "[email protected]";

$message_endpoint = "https://".$api_version.$domain_name."/messages";

$curl = curl_init();
curl_setopt($curl, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
curl_setopt($curl, CURLOPT_MAXREDIRS, 5);
curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($curl, CURLOPT_VERBOSE, 0);
curl_setopt($curl, CURLOPT_HEADER, 0);
curl_setopt($curl, CURLOPT_CONNECTTIMEOUT, 15);
curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, 0);
curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, 0);

curl_setopt($curl, CURLOPT_USERPWD, 'api:' . $api_key);
curl_setopt($curl, CURLOPT_POST, true);
curl_setopt($curl, CURLOPT_URL, $message_endpoint);

$post_data = array(
    'from' => 'System <' . $sender_email . '>',
    'to' => '[email protected]',
    'h:Reply-To' => $reply_address,
    'subject' => 'Document Package ' . date('Y-m-d'),
    'html' => '<p>Please find attached document</p>',
    'attachment[0]' => 'document.zip'
);

curl_setopt($curl, CURLOPT_POSTFIELDS, $post_data);
$response = curl_exec($curl);
curl_close($curl);

$decoded_response = json_decode($response, true);
var_dump($decoded_response);
?>

I’m using my actual Mailgun credentials in the real code. Has anyone successfully implemented file attachments with Mailgun? What am I doing wrong here?

2

The issue arises from passing just a string filename instead of the actual file data. Mailgun requires the file content; therefore, you should utilize CURLFile or the @ syntax for attaching files correctly. Replace your attachment line with: ‘attachment[0]’ => new CURLFile(‘/full/path/to/document.zip’, ‘application/zip’, ‘document.zip’). If you’re on an older PHP version, use ‘attachment[0]’ => ‘@/full/path/to/document.zip’. Ensure the file path is absolute and that the file exists on your server. I encountered a similar problem initially, and this solution worked perfectly for me.

3

yeah your missing the actual file content there. try using curl_file_create() instead - thats the newer way to do it. something like 'attachment[0]' => curl_file_create('/path/to/document.zip') should work better than just passing the filename as string.

4

Your code is treating the attachment as a simple string parameter when it needs to be a proper file object. The main problem is in your $post_data array where you have ‘attachment[0]’ => ‘document.zip’ - this just sends the filename as text rather than the actual file contents. I had this exact same issue when I started working with Mailgun attachments. You need to modify your CURL options to handle multipart form data properly. Before setting your post fields, add curl_setopt($curl, CURLOPT_SAFE_UPLOAD, true); and then change your attachment line to use the full file path with new CURLFile(). Also make sure the file permissions are readable by your web server process, as I spent hours debugging what turned out to be a simple permission issue.