Send Email with PHP

Recommended approach

Use a small application mail adapter. The rest of your PHP code calls that adapter with normalized fields, and the adapter decides whether to send through Postscale REST API or SMTP relay.

This keeps provider details out of controllers, jobs, and model hooks.

REST API example

<?php

$payload = [
    "from" => "Acme <alerts@example.com>",
    "to" => ["user@example.com"],
    "subject" => "Welcome",
    "html_body" => "<p>Hello from Acme</p>",
    "text_body" => "Hello from Acme",
    "tags" => ["onboarding"],
];

$ch = curl_init("https://api.postscale.io/v1/send");
curl_setopt_array($ch, [
    CURLOPT_POST => true,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => [
        "Authorization: Bearer " . getenv("POSTSCALE_API_KEY"),
        "Content-Type: application/json",
    ],
    CURLOPT_POSTFIELDS => json_encode($payload, JSON_THROW_ON_ERROR),
]);

$response = curl_exec($ch);
$status = curl_getinfo($ch, CURLINFO_HTTP_CODE);
curl_close($ch);

if ($status >= 400) {
    throw new RuntimeException("Email send failed: " . $response);
}

Store your own application event ID with the message so a webhook can update the right user, order, or notification later.

SMTP relay for legacy PHP

Use SMTP when the app already has mail settings or uses a framework/plugin that expects SMTP.

Avoid unauthenticated local sendmail or PHP mail() for production transactional email. Those paths make deliverability, DKIM, logs, suppressions, and support harder.

Retry rules

1. Retry network timeouts and temporary 5xx API responses with backoff.
2. Do not retry validation errors until the payload is fixed.
3. Do not generate a new password reset token on every retry.
4. Use webhook retries and idempotency for final state.

Migration checklist

1. Verify the From domain.
2. Publish SPF, DKIM, and DMARC-compatible records.
3. Import suppressions from the old provider.
4. Move one transactional workflow first.
5. Confirm delivery, bounce, defer, and complaint webhooks.
6. Expand after bounce rates and support tickets look normal.

References

• PHP cURL functions
• Symfony Mailer documentation
• Postscale SMTP relay guide
• Postscale transactional email guide