SMTP Senpai

SMTP Senpai connects the email your WordPress site sends (password resets, order emails, contact form notifications and anything else that uses wp_mail()) to SMTP Senpai, the SMTP relay and REST email API by MailSenpai, hosted in the European Union.

You need an SMTP Senpai account to send email through it. The plugin itself is free and has no paid features. SMTP Senpai also has a permanent free sending plan: 5,000 emails per calendar month, up to 200 per day and 30 in the preceding hour, one verified sender domain and 7-day service logs. No card or expiry. Paid sending plans are optional. The local WordPress email log has its own 7, 14 or 30-day retention setting.

Two ways to send

• API key (recommended) – each email is sent with an HTTPS request to the SMTP Senpai API. It works even when your hosting provider blocks outgoing SMTP ports.
• SMTP – WordPress connects to the SMTP Senpai relay (relay.mailsenpai.com, port 2525 or 587, STARTTLS by default) with your SMTP username and password. Host, port and encryption can be changed.

Features

• Its own SMTP Senpai menu: Dashboard, Settings, Test & domain check, Email log and Help.
• Dashboard with the state of the connection, the monthly volume of your plan, the latest emails and the result of the sender domain check.
• Guided setup in three steps (API key, sender on a verified domain, test email) with a progress bar.
• Plain explanations for the common problems (domain not verified, key not valid, account suspended, monthly volume used up, site that cannot reach the service) with a link to the page of the customer area where to fix them.
• Admin bar item with a status symbol (check mark: working, clock: setup not finished or account being activated, warning sign: the last email was not sent) and quick links. Only administrators see it, and it can be turned off in the settings.
• Replaces the WordPress mailer cleanly through the pre_wp_mail filter (API mode) or phpmailer_init (SMTP mode).
• Supports To, Cc, Bcc (up to 50 recipients per email in API mode), Reply-To, HTML and plain-text emails, attachments (up to 10 files, 10 MB in total) and custom X- headers.
• Sender address and name, with an option to force them for every email.
• Optional fallback to the default WordPress mailer if the API cannot accept an email (off by default).
• Send a test email and see the exact answer of the API when something is wrong.
• Sender domain check: SPF, DKIM, DMARC and MX in plain language, with what to fix.
• Account status box: plan volume, emails used and remaining, SMTP details.
• Simple email log (date, status, recipients, subject, error), kept for 7, 14 or 30 days and cleaned up automatically. Message bodies and attachments are never stored. A privacy mode masks the addresses and drops the subjects.
• Secrets are stored encrypted, never autoloaded and never shown again in full. You can also define them in wp-config.php.
• Works on multisite: every site has its own settings and log.
• Translation ready.

No tracking, no ads, no external scripts or fonts: everything the admin pages need (icons, logo, the Poppins font) is bundled with the plugin. Nothing is shown outside the plugin pages except the optional admin bar item.

External services

This plugin connects to services operated by MailSenpai on app.mailsenpai.com. Nothing is sent until you configure the plugin or use one of its tools.

1. SMTP Senpai email API – https://app.mailsenpai.com/relay/v1/invio

• What it is for: delivering the emails of your site when the plugin is set to “API key” mode.
• What is sent and when: every time WordPress sends an email (wp_mail()), the plugin sends the recipients, sender address and name, Reply-To, subject, message body, attachments and custom X- headers of that email, together with your API key. The request also carries the plugin and WordPress version in the User-Agent; the address of your site is not added.

2. SMTP Senpai account status – https://app.mailsenpai.com/relay/v1/stato

• What it is for: checking that the API key is valid and showing the account status box (volume, usage, SMTP details).
• What is sent and when: your API key, when you save a new key, when you open the plugin Dashboard or Settings page (the answer is cached for ten minutes) and when you click “Refresh”. The admin bar item never calls the service: its status comes from the local email log.

3. SMTP relay – relay.mailsenpai.com (or the host you enter)

• What it is for: delivering the emails of your site when the plugin is set to “SMTP” mode.
• What is sent and when: every email sent by WordPress, with your SMTP username and password, over an encrypted connection (STARTTLS by default).

4. Email DNS check – https://app.mailsenpai.com/tools/dns-check

• What it is for: the “Sender domain check” tool.
• What is sent and when: only the domain name you enter and the language of the answer (English or Italian), when you click “Check domain”. No key and no personal data are sent.

The services are provided by MailSenpai: Terms and Conditions · Privacy Policy.