Name: PureMails
Author: purehost

PureMails is a transactional email service sending from Germany. This plugin connects your WordPress website to it.

One-key setup. Paste an API key from the PureMails customer portal; the plugin creates its own SMTP login and picks a verified sender address.
All emails of the website. Contact forms, orders, password resets and newsletters sent with wp_mail() go through PureMails, encrypted and authenticated.
Bounces back into your newsletter tool. Every 15 minutes the plugin fetches bounces and complaints and marks the addresses in MailPoet, The Newsletter Plugin, FluentCRM, Groundhogg, Icegram Express (Email Subscribers & Newsletters), Noptin and AcyMailing: hard bounces and complaints right away, soft bounces after three within 30 days (configurable). Other tools can use the sendmails_ereignis action.
Email log with delivery status. Every email with recipient, subject, the plugin that sent it and its real status at the recipient: delivered, hard or soft bounce with the server response, complaint. Search, filters and, optionally, “Send again”.
Quota and rates in the dashboard. Monthly quota with forecast, bounce and complaint rate, sending rate and limits, deliveries per day, bounces by provider and reason.
Protection against abused forms. If a plugin or theme suddenly sends far more emails than usual, for example because bots flood a contact form, further emails from that source are held until you decide: send, discard or always trust the source.
Warnings before your customers notice. Email to the administrator when the quota reaches 80 or 100 %, the bounce or complaint rate approaches the limit, emails are held or stuck in the queue, or the sender domain is no longer verified. Plus a short weekly report on Mondays.
Safe during disruptions. If PureMails is briefly unreachable, emails wait in a local queue and are retried for up to 24 hours. The plugin switches between the PureMails mail servers automatically.
Domain check, Site Health and WP-CLI. DNS status of every sender domain with copy buttons, tests in Site Health and wp sendmails commands for agencies.
Guided setup with test email and a self-test against two test mailboxes (delivery and bounce).

No open or click tracking. Recipients and subjects stay in the email log for 30 days by default (configurable, or not at all); email content only if you turn it on, for at most 7 days. Credentials are stored encrypted in the database or as constants in wp-config.php.

The plugin requires a PureMails account. Plans and ordering: PureMails.

The user interface is in English; translations are provided through translate.wordpress.org.

External services

This plugin connects to services operated by PureHost (PureMails), the email service it is made for. It does not work without them.

Mail sending (smtp.send-mails.de): every email sent by WordPress after you turn on sending, including recipients, subject, content and attachments, is transmitted via SMTP (TLS, authenticated with your SMTP login) to the mail servers of PureMails for delivery. The plugin only connects to mail servers under PureMails. The test email and the self-test send emails only when you start them.
API (api.send-mails.de): authenticated with your API key. When you save the key and during setup, the plugin sends the address of your website to create an SMTP login for it. Every 15 minutes and when you open the plugin pages, it retrieves your quota, statistics, verified domains, the mail servers to use, new bounce and complaint events (these contain the affected recipient addresses) and the delivery status of recently sent emails (identified by a random ID per email).
Customer portal (portal.send-mails.de): the plugin pages only link to the portal. Nothing is transmitted unless you open a link yourself.

Developers

do_action('sendmails_ereignis', $wirkung, $email, $ereignis): $wirkung is bounced or beschwerde (complaint).
apply_filters('sendmails_ref', $ref): content of the X-SendMails-Ref header.