The install and the honest setup
PHPMailer is the right library if PHP must speak SMTP: actively maintained, handles encoding and attachments, escapes the injection traps mail() invites.
composer require phpmailer/phpmailer $mail = new PHPMailer(true); $mail->isSMTP(); $mail->Host = "smtp.example.com"; $mail->Port = 587; $mail->SMTPAuth = true; $mail->Username = "user"; $mail->Password = "pass"; $mail->setFrom("[email protected]"); $mail->addAddress("[email protected]"); $mail->Subject = "Welcome"; $mail->msgHTML("<p>You're in.</p>"); $mail->send();
What the install doesn't buy you
Deliverability needs more than that: an authenticated domain with SPF, DKIM, and DMARC aligned, warmed sending infrastructure, bounce and complaint handling, and a suppression list. PHPMailer transports; it cannot do any of those.
The comparison worth making is not PHPMailer vs mail(). It's ten lines of SMTP config and credentials vs one cURL POST with a bearer token, where the platform owns the landing.
We know exactly how heavy the real setup feels, because we measured ours: verifying a technical sending domain used to mean adding five DNS records, with four more recommended. Asking a developer to do that during onboarding is a non-starter, so we flipped the default. A fresh account reserves a protected Nitrosend brand subdomain without consuming provider resources. Preparing it creates DNS and provider infrastructure on demand; the first live send waits for readiness and explicit selection, with a 50-recipient rolling-24-hour commercial cap on Free. Composer gives you the library in ten seconds. Your first send deserves the same respect for your time.
Same logic applies to the email itself. Installing a library doesn't design the message any more than it delivers it, which is why I keep a dedicated email design skill on GitHub that does better anti-slop design than any default template. The tooling should raise the craft, not just move the bytes.
Full parameters and responses live in the REST API docs and the API reference.
Go deeper
The one-POST version: send email with PHP. Why the mail() starting point fails: PHP mail via SMTP. The port you pick matters less than the records behind it, so read SMTP ports alongside SPF, DKIM and DMARC authentication.