A plugin to make WordPress outgoing emails better.

The main purpose is to vastly reduce the chances of your emails being marked as spam or being rejected.

This plugin started as a debugging tool to find out why emails were not sent, but has grown into a full-fledged email enhancement plugin.

Please note that this plugin is not a "we support any type of transport" Email plugin. For other protocols than SMTP, but rather to enhance the email sending capabilities of WordPress. If you need to send emails with other protocols than SMTP, this plugin is not for you. You might want to look at plugins like Post SMTP (not affiliated).

And since version 6.0.0, after more than 10 years of development, this plugin is now a FOSS plugin, meaning it is free to use, modify and distribute under the GPLv2 license.

In return, we ask you to support the development of this plugin by contributing to the codebase, reporting bugs, and helping others in the community.

If you find a vulnerability, please email us at responsibledisclosure@acato.nl.

From version 4.1.0 on, the plugin is fully WP Coding standards compliant and fully Namespaced. The side effect is that While versions 4.0.0 - 4.0.2 are backwards compatible; version 4.1.0 is NOT -- IF -- you access the WP_Email_Essentials methods directly. In version 6.0.0 the namespace is changed to Acato\Email_Essentials but backward compatibility is available.

Please TEST your website with the latest version of WPES locally or on a test-server BEFORE you update your live website.

• Set a good From name and email address, automatically correcting it if needed. For example, a contact form is sent from the visitors email address, resulting in an invalid Sender address. This plugin will correct it to a valid email address. This plugin automatically corrects it.
• Correct envelope-from address; often forgotten, but important for deliverability.
• Reformat as HTML with plain text alternative; will detect the use of HTML ensures that emails are sent as HTML with a plain text alternative.
• Process shortcodes in your email content.
• UTF8 recoding, to ensure that special characters are correctly encoded in the email.
• Email Essentials allows for adding CSS, header, footer, and body template using filters, see below.
• Convert CSS to inline styles for better support in email clients
• SMTP configuration
• Send emails to multiple addressees as separate emails
• S/MIME signing, using a supplied certificate, to ensure the authenticity of the email.
• DKIM signing, and providing all information needed to set up DKIM signing for your domain.
• Allow redirecting emails sent to the administrator to other email addresses based on the email subject.
• Allow redirecting emails sent to the moderators (e.g., for comments).
• Keep a history of outgoing emails (debugging, cleared on deactivation)
• Email receipt tracking (for investigative purposes only, see GDPR note)
• Re-send button for failed emails
• Allow sending emails delayed, to prevent sending too many emails at once. (Beta feature)

This tool is created for people that know what to do and why they do it. If you don't know what a feature does, ask for help :)

*1) Under GDPR, storing and tracking emails is prohibited, the history feature is meant for investigative purposes only!

acato_email_essentials_settings

Parameters:

• (array) $settings The current settings of the plugin.

Expected return:

• (array) The new settings of the plugin.

acato_email_essentials_defaults

Parameters:

• (array) $defaults The current default settings of the plugin.

Expected return:

• (array) The new default settings of the plugin.

acato_email_essentials_subject

Parameters:

• (string) $the_subject Subject for the email.
• (PHPMailer) $mailer The PHPMailer object (by reference).

Expected return:

• (string) The (altered) Subject.

acato_email_essentials_body

Parameters:

• (string) $should_be_html A text that should be html, but might not yet be, your job to make a nice HTML body.
• (PHPMailer) $mailer The PHPMailer object (by reference).

Expected return:

• (string) A text that should be html.

acato_email_essentials_head

Parameters:

• (string) $the_head_section HTML that is the HEAD section of the HTML email.
• (PHPMailer) $mailer The PHPMailer object (by reference).

Expected return:

• (string) The altered HEAD section of the HTML email.

acato_email_essentials_css

Parameters:

• (string) $the_css CSS for the email (empty by default).
• (PHPMailer) $mailer The PHPMailer object (by reference).

Expected return:

• (string) The (altered) CSS.

acato_email_essentials_minify_css

Parameters:

• (string) $css CSS to be minified.

Expected return:

• (string) The minified CSS.

acato_email_essentials_mail_is_throttled

Parameters:

• (bool) $is_throttled Whether the mail is currently throttled.
• (string) $ip The sender's IP address.
• (int) $mails_recently_sent Number of mails recently sent from this IP.

Expected return:

• (bool) Whether the mail should be throttled.

acato_email_essentials_mail_throttle_time_window

Parameters:

• (int) $time_window Time window in seconds for counting sent emails.

Expected return:

• (int) The (altered) time window in seconds.

acato_email_essentials_mail_throttle_max_count_per_time_window

Parameters:

• (int) $count Maximum number of emails allowed per time window.

Expected return:

• (int) The (altered) maximum count.

acato_email_essentials_mail_throttle_batch_size

Parameters:

• (int) $size Number of emails to send in a single batch.

Expected return:

• (int) The (altered) batch size.

acato_email_essentials_ip_services

Parameters:

• (array) $services The current list of IP services used to determine the sender's IP address.

The services must be keyed with ipv4, ipv6 and dual-stack. The values must be URLs that return the IP address in plain text. The dual-stack service should return an IPv6 address if available, otherwise an IPv4 address, never both.

You can set-up your own service like this;

• You will need a webserver that can run PHP, and you need a DNS service that allows you to manually add records.
• You will need three webspaces, for example; ipv4.myservice.com, ipv6.myservice.com and dual-stack.myservice.com.
  • You could use the same webspace for all three, but you will still need three subdomains on the service.
• For the ipv4 subdomain, ONLY register an A record, pointing to the webserver's IP address.
• For the ipv6 subdomain, ONLY register an AAAA record, pointing to the webserver's IPv6 address.
• For the dual-stack subdomain, register both an A and an AAAA record, pointing to the webserver's IP addresses.
• Create a file called index.php in each of the webspaces with the following content:

<?php
header('Content-Type: text/plain');
print $_SERVER['REMOTE_ADDR'];

That's it. You can now use these services in the plugin settings like this;

add_filter('acato_email_essentials_ip_services', 'my_custom_ip_services');
function my_custom_ip_services($services) {
    // Add your custom services here
    $services['ipv4'] = 'https://ipv4.myservice.com';
    $services['ipv6'] = 'https://ipv6.myservice.com';
    $services['dual-stack'] = 'https://dual-stack.myservice.com';
    return $services;
}

Expected return:

• (array) The (altered) list of IP services.

acato_email_essentials_ip_service

Parameters:

• (string) $service The URL of the IP service for the given type.
• (string) $type The type of IP service ('ipv4', 'ipv6', or 'dual-stack').

Expected return:

• (string) The (altered) IP service URL.

Filter to modify individual IP service URLs based on type.

acato_email_essentials_website_root_path

Parameters:

• (string) $path The current website root path.

Expected return:

• (string) The (possibly altered) website root path.

Filter to supply the correct website root path in case of non-standard setups.

acato_email_essentials_development_tlds

Parameters:

• (array) $tlds Array of top-level domains considered as development environments.

Expected return:

• (array) The (altered) array of development TLDs.

Filter to modify which TLDs are treated as development/local environments. Default values are 'local' and 'test'.

in the public/scripts and public/styles folder you find the JS and CSS files used in the plugin admin area. These files are processed with Webpack, just so it works in all recent browsers. Script is nearly identical to the source.

You can find the source files in the src/scripts and src/styles folders.

If you feel the need to modify these files, you can change them there, and run npm install ; npm run build to create the production files.

You can use npm run i18n to generate the POT file for translation, update the PO files in the languages folder, and compile to MO/php files. This is a one-task-does-all; run it, change the translations, run it again. Done. See package.json for more details or individual commands.

In the tools folder you will find a script to generate DKIM keys, should you want to use DKIM signing. rename to remove the .txt extension and run it in a shell.

Tools are provided as-is, without support. Use at your own risk. Read the scripts before using them.

You DO NOT HAVE TO USE these scripts, you can generate DKIM keys with any tool you like.

Please find the changelog in the readme.txt file.