Perl
Mailgun Send Send HTML Email with Attachments and HTML Images

Sends an HTML email with images and attachments.
Chilkat Perl Downloads

Perl
use chilkat();

$success = 0;

# This example assumes the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

$http = chilkat::CkHttp->new();

$http->put_Login("api");
$http->put_Password("sending_api_key");#  Replace with your actual sending API key.

$req = chilkat::CkHttpRequest->new();
$req->put_HttpVerb("POST");
$req->put_Path("/v3/YOUR_DOMAIN_NAME/messages");
$req->put_ContentType("multipart/form-data");

# Change YOUR_DOMAIN_NAME to something like "mg.your-domain.com".
$req->AddParam("from",'Your Name <mailgun@YOUR_DOMAIN_NAME>');
$req->AddParam("to",'Joe Example <joe@example.com>');
$req->AddParam("subject","Hello Joe Example");
$req->AddParam("html","<html><body><b>This is the HTML body</b><br><img src=\"cid:cidStarfish.jpg\"></body></html>");

# An a attachd file
$bd = chilkat::CkBinData->new();
$success = $bd->LoadFile("qa_data/hamlet.zip");
if ($success == 0) {
    print "Failed to load file attachment." . "\r\n";
    exit;
}

$req->AddBdForUpload("attachment","hamlet.zip",$bd,"application/zip");

# add an image as CID
$success = $bd->LoadFile("qa_data/jpg/starfish.jpg");
if ($success == 0) {
    print "Failed to load HTML image." . "\r\n";
    exit;
}

$req->AddBdForUpload("inline","cidStarfish.jpg",$bd,"image/jpeg");

$resp = chilkat::CkHttpResponse->new();
$success = $http->HttpSReq("api.mailgun.net",443,1,$req,$resp);
if ($success == 0) {
    print $http->lastErrorText() . "\r\n";
    exit;
}

$sbResponseBody = chilkat::CkStringBuilder->new();
$resp->GetBodySb($sbResponseBody);
$jResp = chilkat::CkJsonObject->new();
$jResp->LoadSb($sbResponseBody);
$jResp->put_EmitCompact(0);

print "Response Body:" . "\r\n";
print $jResp->emit() . "\r\n";

$respStatusCode = $resp->get_StatusCode();
print "Response Status Code = " . $respStatusCode . "\r\n";
if ($respStatusCode >= 400) {
    print "Response Header:" . "\r\n";
    print $resp->header() . "\r\n";
    print "Failed." . "\r\n";
    exit;
}

# Sample JSON response:
# (Sample code for parsing the JSON response is shown below)

# {
#   "id": "<20210429234809.1.2D550E1C94D3D98F@sandbox0e542e4c577f4bbb98c8bf6b6bca727b.mailgun.org>",
#   "message": "Queued. Thank you."
# }

# Sample code for parsing the JSON response...
# Use the following online tool to generate parsing code from sample JSON:
# Generate Parsing Code from JSON

$id = $jResp->stringOf("id");
$message = $jResp->stringOf("message");