Sending Email With PHPMailer

PHPMailer is the most widely used library for sending email from PHP. It wraps SMTP so you configure a host, port, and credentials once, then build and send messages with a clear object API. PHP's built-in mail() function does too little (no authentication, weak error reporting), which is why most projects reach for PHPMailer instead. Here is a complete, working send.

How do you install PHPMailer?

Use Composer:

composer require phpmailer/phpmailer

Then load the autoloader and import the classes you need:

<?php
require "vendor/autoload.php";

use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\Exception;

How do you configure SMTP and send a message?

Create a PHPMailer instance, switch it into SMTP mode with isSMTP(), then set the connection and message fields. Wrap the call in try/catch so a failed send is reported rather than swallowed:

<?php
$mail = new PHPMailer(true); // true enables exceptions

try {
    // Server settings
    $mail->isSMTP();
    $mail->Host       = "smtp.example.com";
    $mail->SMTPAuth   = true;
    $mail->Username   = getenv("SMTP_USER");
    $mail->Password   = getenv("SMTP_PASS");
    $mail->SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS;
    $mail->Port       = 587;

    // Recipients
    $mail->setFrom("you@yourdomain.com", "Your App");
    $mail->addAddress("recipient@example.org", "Recipient Name");

    // Content
    $mail->isHTML(true);
    $mail->Subject = "Your receipt";
    $mail->Body    = "<p>Thanks for your order.</p>";
    $mail->AltBody = "Thanks for your order. This is the plain-text version.";

    $mail->send();
    echo "Message sent.";
} catch (Exception $e) {
    echo "Send failed: {$mail->ErrorInfo}";
}

A few details that trip people up. SMTPSecure and Port go together: use ENCRYPTION_STARTTLS with 587, or ENCRYPTION_SMTPS with 465. isHTML(true) tells PHPMailer the Body is HTML and to send AltBody as the plain-text alternative. Pass true to the constructor so failures throw an Exception instead of returning false silently.

How do you add an attachment?

Call addAttachment with a file path before send():

<?php
$mail->addAttachment("./invoices/invoice-1042.pdf", "invoice.pdf");

The second argument renames the file as the recipient sees it. You can call it more than once for multiple attachments.

Send it with Bird

PHPMailer talks SMTP, which means production needs a mail server with a clean reputation, correct authentication records, and somewhere to see what happened after sending. An HTTP API removes the server. You send JSON over HTTPS and get a structured response. With the Bird email API the same message is one call:

use Bird\Bird;

$bird = new Bird(getenv("BIRD_API_KEY"));

$bird->emails->send([
  "from"    => "you@yourdomain.com",
  "to"      => "delivered@bird.dev",
  "subject" => "Hello from PHP",
  "html"    => "<p>It works.</p>",
]);

The delivered@bird.dev sandbox address always accepts mail, so you can verify the integration before sending to real inboxes. No SMTP socket, no port choice, no reputation to warm yourself.

FAQ

Why not just use PHP's mail() function?

mail() hands the message to the local sendmail binary with no SMTP authentication and almost no error reporting. PHPMailer authenticates against a remote server, supports TLS, builds multipart messages, and tells you why a send failed.

What is the difference between Body and AltBody?

Body is the HTML version and AltBody is the plain-text fallback. With isHTML(true) set, clients that cannot render HTML show AltBody, which also helps with deliverability.

STARTTLS or SMTPS?

ENCRYPTION_STARTTLS on port 587 upgrades a plain connection to TLS, while ENCRYPTION_SMTPS on port 465 is encrypted from the start. Match the setting to the port your mail server expects.

PHPMailer is the right tool when you want to send over SMTP from PHP. When you would rather skip operating the server, the sending email guide shows the API path in full.