Title: Lynbro SMTP Mailer Author: lynbro Published: November 10, 2026 Last modified: November 12, 2026 --- Search plugins ![](https://ps.w.org/lynbro-smtp-mailer/assets/banner-772x250.png?rev=3794877) ![](https://ps.w.org/lynbro-smtp-mailer/assets/icon-256x256.png?rev=3794877) # Lynbro SMTP Mailer By [lynbro](https://profiles.wordpress.org/lynbro/) [Download](https://downloads.wordpress.org/plugin/lynbro-smtp-mailer.1.1.2.zip) * [Details](https://wordpress.org/plugins/lynbro-smtp-mailer/#description) * [Reviews](https://wordpress.org/plugins/lynbro-smtp-mailer/#reviews) * [Installation](https://wordpress.org/plugins/lynbro-smtp-mailer/#installation) * [Development](https://wordpress.org/plugins/lynbro-smtp-mailer/#developers) [Support](https://wordpress.org/support/plugin/lynbro-smtp-mailer/) ## Description By default WordPress sends email with PHP `mail()`, which Gmail, Outlook and most inboxes treat as suspicious. Password resets, WooCommerce orders and contact-form messages end up in spam, or never arrive at all. **Lynbro SMTP** sends every WordPress email through a real, authenticated SMTP server — your host’s, your mailbox’s, or a sending service such as Brevo, SendGrid, Mailgun, Amazon SES or Postmark. And when something goes wrong, you find out, and the email is not lost. Everything is in this free plugin. There is no Pro version, no nag screens, no “ upgrade” buttons, no weekly emails from us and no other plugins installed behind your back. #### Why another SMTP plugin? The well-known SMTP plugins either sell the email log, resend, backup connection and alerts as a paid add-on, or give them away with a large interface built around API mailers and OAuth apps. Lynbro SMTP Mailer does one thing — plain, authenticated SMTP — and adds what those leave out: * **Private by default:** the log keeps message content only for failed emails, so password-reset links of a working site never sit in your database (one SMTP plugin’s log was readable without login in 2025, CVE-2025-11833). * **Backup inside the same send:** the visitor’s form gets “sent”, not an error, while the main server is down. * **Staging modes:** redirect every email to one address with Cc and Bcc removed, or send nothing and only log — safe copies of a live shop. * **Plain-language diagnostics:** the SMTP conversation with the password hidden, advice for the usual errors, a port check from your server and a local SPF/DMARC check (no external API). * **Hosts people actually use in Denmark and the EU:** presets for Simply.com, one.com, IONOS, Brevo, Mailgun EU, Zoho EU next to the global ones. #### What you get * **Any SMTP server** — presets for Gmail / Google Workspace, Outlook / Microsoft 365, Brevo, SendGrid, Mailgun, Amazon SES, Postmark, Zoho, Mailjet, SMTP2GO, Simply.com, one.com and IONOS, each with a one-line hint on what the username and password are. * **Email log** — every email with recipients (including Cc and Bcc), subject, status, the connection that sent it and the exact error. Search, filter by status, export to CSV. * **Resend** — failed emails keep their content, so one click sends them again. * **Backup connection** — when the main server fails, the same email goes out at once through a second SMTP server or PHP `mail()`, in the same request. The visitor never sees an error. * **Failure alerts** — an email (sent with PHP `mail()`, because your SMTP server may be what is down) and/or a webhook (Slack and Discord incoming webhooks, or your own endpoint: JSON with `text` and `content`). At most one per hour. * **Test & diagnostics** — a test email with the full SMTP conversation (password hidden) and plain-language advice for the usual errors; a check of outgoing ports 587, 465, 25 and 2525; the SPF and DMARC records of your sender domain. * **Staging modes** — send everything to one address (Cc and Bcc dropped, so real customers never get a copy), or send nothing at all and only log. * **Sender control** — force the From address (and, separately, the From name), set a default Reply-To that is used only when an email has none, and send bounces to the From address. * **Credentials in wp-config.php** — define `LYNBRO_SMTP_HOST`, `LYNBRO_SMTP_USER`,` LYNBRO_SMTP_PASS` and friends to keep the login out of the database. Otherwise the password is encrypted with your site’s keys. * **Import** host, port and sender from WP Mail SMTP, FluentSMTP, Easy WP SMTP or Post SMTP in one click. * **WP-CLI** — `wp lynbro-smtp test`, `log`, `resend`, `purge`, `status`. * **Site Health** test and a small Dashboard widget with the last seven days. #### Private by default * The log keeps message content **only for failed emails** (so they can be resent), unless you choose otherwise. Password-reset links of a working site therefore never sit in the log. * Entries are deleted after 30 days (you choose 1–365). * The log is visible only to administrators; every action checks permissions and a security token. There is no public endpoint. * Log entries are part of **Tools Export / Erase Personal Data**. * The plugin contacts no Lynbro service and collects no statistics. ### External Services Lynbro SMTP connects to **no service run by Lynbro**. It connects only to: * **The SMTP server(s) you enter** in its settings (main and, if set, backup), to deliver your site’s outgoing email. Each email’s recipients, headers, content and attachments are sent to that server when WordPress sends the email. Which provider that is, and its terms and privacy policy, is your choice. * **A webhook URL, only if you enter one** under Failure alerts. When an email fails, the plugin sends the error message, your site name and a link to your email log to that URL. Nothing is sent when the field is empty. Test emails and alerts are sent only when you or a failure trigger them. The plugin also reads public DNS records (SPF, DMARC) of your sender domain through your server’s normal DNS resolver when you open the Test tab. **WordPress.org plugin directory (the shared Lynbro “Our plugins” screen).** Apart from the above, one request goes to WordPress.org, from every Lynbro plugin alike: when an administrator who may install plugins opens Lynbro Our plugins, the screen asks the WordPress.org Plugin Directory API (https://api.wordpress.org/plugins/info/ 1.2/) which Lynbro plugins are listed, through WordPress core’s own `plugins_api()`— the same call the Plugins Add New screen makes. * **What is sent:** the query (plugins by the author “lynbro”), plus what WordPress core adds to every request to WordPress.org: your WordPress version, the admin language and, in the User-Agent, your site address. Nothing about your visitors, users or content. * **When:** only on that screen, at most once a day (the answer is cached for a day; after a failed request, an hour). No other screen and no visitor request triggers it. * Installing a suggested plugin uses WordPress core’s own installer, which downloads the plugin from downloads.wordpress.org — only when you click “Install now”. * WordPress.org [Terms of Service](https://wordpress.org/about/terms-of-service/)· [Privacy Policy](https://wordpress.org/about/privacy/) ### Privacy The email log is stored in your own database (table `{prefix}lynbro_smtp_log`): date, recipients, Cc, Bcc, Reply-To, subject, headers, status, connection, error and — only for failed emails by default — the message content. Entries are deleted automatically after the retention period (30 days by default) and on uninstall. Log entries are included in WordPress’ personal data export and erasure tools. ## Screenshots [⌊Settings — provider presets, login, sender, backup connection, delivery mode, log and alerts.⌉⌊Settings — provider presets, login, sender, backup connection, delivery mode, log and alerts.⌉[ Settings — provider presets, login, sender, backup connection, delivery mode, log and alerts. [⌊Test & diagnostics — test email with the SMTP conversation, port check, SPF and DMARC.⌉⌊Test & diagnostics — test email with the SMTP conversation, port check, SPF and DMARC.⌉[ Test & diagnostics — test email with the SMTP conversation, port check, SPF and DMARC. [⌊Email log — status, recipients, connection used, error and one-click resend.⌉⌊ Email log — status, recipients, connection used, error and one-click resend.⌉[ Email log — status, recipients, connection used, error and one-click resend. [⌊Port check from the web server to the SMTP host, with SPF and DMARC of the sender domain.⌉⌊Port check from the web server to the SMTP host, with SPF and DMARC of the sender domain.⌉[ Port check from the web server to the SMTP host, with SPF and DMARC of the sender domain. ## Installation 1. Install from **Plugins Add New** (search for “Lynbro SMTP Mailer”) or upload the ZIP, then activate. 2. Open **Lynbro SMTP**. 3. Pick your provider, enter the username and password, set the From email, and save. 4. Open **Test & diagnostics** and send a test email. Switching from another SMTP plugin? Use **Import settings from …** on the Settings tab, enter the password once, then deactivate the old plugin. ## FAQ ### Which SMTP provider should I use? Your host’s mail server or your own mailbox works for small sites. For shops and anything with more than a few dozen emails a day, a sending service (Brevo, Mailgun EU, Amazon SES, Postmark, SendGrid) delivers better. All of them work with plain SMTP. ### Gmail or Microsoft 365 says the password is wrong Both need an app password, not your normal password, when two-step sign-in is on. Microsoft 365 also needs “Authenticated SMTP” enabled for the mailbox, and Microsoft is retiring password sign-in for SMTP — if it is switched off for your tenant, use a sending service instead. The Test tab tells you which of these it is. ### Does Lynbro SMTP support Gmail or Microsoft OAuth (“Sign in with Google”)? No. OAuth needs an app verified by Google or Microsoft, which is the most common source of breakage in other SMTP plugins. App passwords and SMTP relays do the same job without it. ### Is my SMTP password safe? It is encrypted with libsodium using your site’s secret keys, never shown again, never written to the log and left out of the settings export. For the strongest setup, define it as `LYNBRO_SMTP_PASS` in `wp-config.php` — then it is not in the database at all. ### What happens when my SMTP server is down? With a backup connection set, the email goes through the backup in the same request. Without one, it is logged as failed with its content kept, an alert goes out if you set one up, and you can resend it from the log when the server is back. ### My host blocks port 587 / 465 Run **Check ports** on the Test tab. Many sending services also listen on 2525. Otherwise ask your host to open the port. ### Can I use it on a staging copy without emailing real customers? Yes. Choose **Test mode** to send every email to your own address (Cc and Bcc are removed), or **Do not send any email** to only log them. ### Does it work with WooCommerce and form plugins? Yes. Lynbro SMTP works through `wp_mail()`, which WooCommerce, Contact Form 7, WPForms, Gravity Forms, Fluent Forms and almost every other plugin use. Plugins with their own built-in SMTP client (some booking plugins) bypass `wp_mail()` and need their own settings. ### Another SMTP plugin is active — is that a problem? Yes: two plugins configuring the same email fight over it. Lynbro SMTP lists the other mail plugins it finds; deactivate them after importing their settings. ### Is there a paid version? No, and there will not be one with locked features. Lynbro makes several free plugins; paid services, if any, live on our website and are never required. ## Reviews There are no reviews for this plugin. ## Contributors & Developers “Lynbro SMTP Mailer” is open source software. The following people have contributed to this plugin. Contributors * [ lynbro ](https://profiles.wordpress.org/lynbro/) “Lynbro SMTP Mailer” has been translated into 1 locale. Thank you to [the translators](https://translate.wordpress.org/projects/wp-plugins/lynbro-smtp-mailer/contributors) for their contributions. [Translate “Lynbro SMTP Mailer” into your language.](https://translate.wordpress.org/projects/wp-plugins/lynbro-smtp-mailer) ### Interested in development? [Browse the code](https://plugins.trac.wordpress.org/browser/lynbro-smtp-mailer/), check out the [SVN repository](https://plugins.svn.wordpress.org/lynbro-smtp-mailer/), or subscribe to the [development log](https://plugins.trac.wordpress.org/log/lynbro-smtp-mailer/) by [RSS](https://plugins.trac.wordpress.org/log/lynbro-smtp-mailer/?limit=100&mode=stop_on_copy&format=rss). ## Changelog #### 1.1.2 * Readme: External Services now names the one WordPress.org request the shared “ Our plugins” screen makes — what is sent, when, and the WordPress.org terms and privacy policy. * The plugin names and descriptions on “Our plugins” and in the suggestions are translatable. * Links on Lynbro screens use the darker brand green, which meets WCAG AA contrast on the admin background. #### 1.1.1 * Shared Lynbro admin 1.1.0: after two weeks of use and a first success (for example settings saved), this plugin’s own screen asks once, politely and without stars, whether it is doing its job. Answers are per user: “Maybe later” or “Don’t ask again”, and only one Lynbro plugin asks in any 30 days. * A small “Suggested for this site” block under the plugin’s main screen lists Lynbro plugins that fit what the site already uses (WooCommerce, forms, a Danish setup …), with the reason. It can be hidden; nothing installs on its own and nothing is sent anywhere. * Tab labels on Lynbro screens meet WCAG AA contrast. * Lynbro admin screens now read the plugin’s bundled translations (languages/) when WordPress has no language pack for it, so a Danish admin sees Danish instead of English. #### 1.1.0 * New: email log in its own table — Cc, Bcc, Reply-To, status, connection and error; search, filter, paging, CSV export, bulk delete. * New: resend failed emails from the log or with WP-CLI. * New: backup connection (second SMTP server or PHP mail()) used inside the same send. * New: failure alerts by email and webhook, Site Health test, Dashboard widget. * New: Test & diagnostics tab — SMTP conversation with hidden credentials, error advice, port check, SPF/DMARC check. * New: provider presets, wp-config.php constants, separate force-From name, default Reply-To, Return-Path. * New: staging modes (redirect all email to one address, or do not send). * New: import from WP Mail SMTP, FluentSMTP, Easy WP SMTP and Post SMTP. * New: WP-CLI commands; personal data export and erasure. * Fix: the settings page printed a piece of PHP code as text, and the Tools export did not know the plugin’s settings. * Privacy: message content is kept only for failed emails by default; passwords are left out of the settings export. #### 1.0.0 * Initial version: SMTP override, encrypted password storage, force-from, test send, rolling delivery log. ## Meta * Version **1.1.2** * Last updated **10 hours ago** * Active installations **Fewer than 10** * WordPress version ** 6.2 or higher ** * Tested up to **7.1.4** * PHP version ** 7.4 or higher ** * Languages * [Danish](https://da.wordpress.org/plugins/lynbro-smtp-mailer/) and [English (US)](https://wordpress.org/plugins/lynbro-smtp-mailer/). * [Translate into your language](https://translate.wordpress.org/projects/wp-plugins/lynbro-smtp-mailer) * Tags * [deliverability](https://wordpress.org/plugins/tags/deliverability/)[email](https://wordpress.org/plugins/tags/email/) [email log](https://wordpress.org/plugins/tags/email-log/)[smtp](https://wordpress.org/plugins/tags/smtp/) [wp-mail](https://wordpress.org/plugins/tags/wp-mail/) * [Advanced View](https://wordpress.org/plugins/lynbro-smtp-mailer/advanced/) ## Ratings No reviews have been submitted yet. [Your review](https://wordpress.org/support/plugin/lynbro-smtp-mailer/reviews/#new-post) [See all reviews](https://wordpress.org/support/plugin/lynbro-smtp-mailer/reviews/) ## Contributors * [ lynbro ](https://profiles.wordpress.org/lynbro/) ## Support Got something to say? Need help? [View support forum](https://wordpress.org/support/plugin/lynbro-smtp-mailer/)