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WordPress

Send WordPress email through usend with an SMTP plugin.

WordPress sends mail with PHP's mail(), which most hosts and mailbox providers distrust. An SMTP plugin makes it send through usend instead: password resets, WooCommerce receipts and contact-form mail all go through the same pipeline and appear in your dashboard. Reference: Send with SMTP.

Before you start

  1. Verify the domain you use as the site's sender (acme.com).
  2. Create a sending_access API key, limited to that domain if you like.

Settings

Any SMTP plugin works (WP Mail SMTP, FluentSMTP, Post SMTP and others). Choose its Other SMTP or Custom SMTP option and enter:

FieldValue
SMTP hostsmtp.usend.et
EncryptionTLS (STARTTLS) with port 587, or SSL with port 465
Port587 or 465
AuthenticationOn
Usernameusend
PasswordYour API key (us_...)
From emailAn address on your verified domain, for example [email protected]
From nameYour site name

Menu names differ between plugins. If the plugin has a "force from email" option, turn it on: other plugins that set a different From address would otherwise be refused by usend with a 554.

Without a plugin

Put the settings in wp-config.php only if your plugin reads constants; otherwise a few lines in a small must-use plugin work:

wp-content/mu-plugins/usend-smtp.php
<?php
add_action('phpmailer_init', function ($phpmailer) {
    $phpmailer->isSMTP();
    $phpmailer->Host       = 'smtp.usend.et';
    $phpmailer->SMTPAuth   = true;
    $phpmailer->Port       = 587;
    $phpmailer->SMTPSecure = 'tls';
    $phpmailer->Username   = 'usend';
    $phpmailer->Password   = defined('USEND_API_KEY') ? USEND_API_KEY : '';
});
add_filter('wp_mail_from', fn () => '[email protected]');

Define USEND_API_KEY in wp-config.php, outside the web root if you can.

Test

Use the plugin's Send a test email button, then check Emails in the usend dashboard.

Troubleshooting

  • Nothing arrives, no error: the site still uses mail(). Check that the plugin is active and its mailer is set to SMTP.
  • 535: wrong key. 554: the From address is not on a verified domain, or the organization is in the sandbox.
  • Connection fails: some hosts block outbound 587 and 465. Ask the host, or use a plugin that supports an HTTP API and the usend API.