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 ·
  Privacy Policy

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.