Description
Prostyle SMTP configures the WordPress PHPMailer through official WordPress hooks. Version 1.1.1 supports WordPress Default Mail, classic SMTP delivery with freely configurable host, port, encryption and authentication, hosting relays, Microsoft 365 OAuth2 / XOAUTH2, reports, scheduled report emails, and the first step of a per-user admin language architecture.
The plugin does not add telemetry, does not display advertising and does not include upsells. OAuth2 connections are optional and are started only after an administrator configures the provider and clicks the connect button.
SMTP passwords, OAuth client secrets and OAuth tokens are encrypted locally with AES-256-GCM and WordPress salts. Email message bodies and attachment contents are never stored by the mail log.
Each wp_mail() call can receive a request-local Request ID and a unique Trace ID. Normal emails run without SMTP debugging. Detailed SMTP diagnostics are captured only for explicitly started diagnostic test emails and are redacted before display or download.
Prostyle SMTP does not retry, queue or resend emails. A successful technical hand-off means that WordPress or the configured mail server processed the message; it does not guarantee inbox placement.
External services
When Microsoft 365 OAuth2 is selected and an administrator starts the connection, the plugin sends the administrator to the Microsoft identity platform and exchanges authorization or refresh tokens with Microsoft token endpoints. The requested delegated SMTP scope is https://outlook.office.com/SMTP.Send plus offline_access for refresh tokens. Microsoft privacy information: https://privacy.microsoft.com/privacystatement
OAuth2 is optional. No OAuth authorization, token exchange or token refresh request is sent unless an administrator configures and connects the selected provider. The plugin does not send diagnostic data to Prostylemedia automatically.
Privacy
Prostyle SMTP can store a local technical mail log when logging is enabled. The log can include timestamps, delivery status, SMTP metadata, the mail origin, attachment count, masked or full recipient addresses depending on the selected setting, and optionally the email subject.
New installations use masked recipient storage by default and do not store email subjects by default. Administrators can disable logging, change recipient storage, enable or disable subject storage, set a retention period, limit the maximum number of log entries, delete logs and export CSV files.
Email message bodies, HTML content, plain text content, attachment contents, attachment paths, SMTP passwords, OAuth client secrets, OAuth tokens and authentication data are not stored in the mail log.
Report emails contain only aggregated delivery statistics from the local log and no message content, attachments or credentials. A successful report status means technical processing by WordPress or the configured mail server, not guaranteed inbox delivery.
Diagnostic exports are generated only after an administrator action. They are designed to exclude passwords, authentication headers, cookies, nonces, tokens, full server paths and email message bodies. Theme and plugin lists are disabled by default for new installations and can be enabled by administrators for support cases.
The plugin does not add telemetry and does not send diagnostic data to Prostylemedia or third-party services automatically.
Assets and Licensing
The plugin code is licensed under GPLv2 or later. The included Prostylemedia logo assets were created for Prostylemedia and are included by the plugin author for use with this GPL-compatible plugin distribution. No third-party JavaScript or CSS libraries are bundled.
Uninstall
Deactivating the plugin keeps settings and logs. Deleting the plugin through WordPress runs uninstall.php and removes plugin-owned settings, transients, database tables, cron hooks, metadata and plugin-owned files.
Screenshots
Installation
- Upload the release ZIP through Plugins > Add New > Upload Plugin.
- Activate Prostyle SMTP.
- Open Prostyle SMTP > SMTP Settings.
- Choose a provider and enter the SMTP or OAuth values from your mail provider or hosting provider.
- Save the settings.
- Send a test email from the Email Test screen.
FAQ
-
Does the plugin support Microsoft 365 OAuth?
-
Yes. Version 1.1.1 supports Microsoft 365 business and school accounts through OAuth2 / XOAUTH2. Administrators must create their own Microsoft Entra app, enter the redirect URI shown by the plugin exactly, add the delegated SMTP.Send permission, store the Client Secret value in the plugin and connect the mailbox deliberately.
-
Does the plugin support Gmail OAuth2?
-
Gmail OAuth2 is shown as in development, but it is not selectable and not available in version 1.1.1.
-
What is WordPress Default Mail?
-
WordPress Default Mail uses the normal wp_mail() and PHPMailer path without configuring SMTP credentials in the plugin. The actual transport is provided by the hosting or PHP mail environment. Prostyle SMTP can still provide sender controls, logging, reports, test emails and diagnostics.
-
What happens to existing SMTP settings after updating?
-
Existing installations stay on the classic SMTP provider. Existing host, port, username, password and sender settings are preserved.
-
Does the plugin store email content?
-
No. The mail log never stores message bodies, HTML content, plain text content or attachment contents.
-
Does “successfully sent” mean that the email reached the inbox?
-
No. It means WordPress or the configured mail server technically processed the message. Spam filters, SPF, DKIM, DMARC, mailbox rules and sender reputation can still affect delivery.
-
Does the plugin work with form plugins?
-
Yes, if the form plugin uses the normal WordPress wp_mail() path. Prostyle SMTP configures PHPMailer for regular WordPress mail delivery instead of replacing form plugin logic.
-
What is a hosting relay?
-
A hosting relay is an SMTP service provided by a web host for sending mail from websites hosted on that infrastructure. The required host, port, encryption and authentication settings depend on the hosting provider.
-
Why does the password or Client Secret field stay empty after saving?
-
SMTP passwords and OAuth Client Secrets are encrypted locally and are not shown again in the input field after saving. The plugin shows a status message when a credential is stored.
-
Which credentials does the plugin store?
-
The plugin can store classic SMTP passwords, OAuth Client Secrets and OAuth access or refresh tokens. These values are encrypted locally. Email bodies, attachments and authentication headers are not stored in the mail log.
-
What do reports show?
-
Reports summarize the local mail log. They show send attempts, successful and failed technical hand-offs, success rate, provider breakdown, common error classes and daily activity for 7 days, 30 days or the current month. Report emails and test reports are excluded from the statistics so reports do not count themselves.
-
What do report emails contain?
-
Report emails use an HTML layout with a plain-text fallback. They include local branding, KPI summaries, provider and error breakdowns, a delivery notice and a link back to the reports screen. They do not contain email bodies, attachments, SMTP passwords, OAuth Client Secrets, OAuth tokens or tracking pixels.
Reviews
There are no reviews for this plugin.
Contributors & Developers
“Prostylemedia SMTP” is open source software. The following people have contributed to this plugin.
Contributors
Translate “Prostylemedia SMTP” into your language.
Interested in development?
Browse the code, check out the SVN repository, or subscribe to the development log by RSS.
Changelog
1.1.1
- Added WordPress Default Mail as a monitored sending method.
- Added provider-specific sender controls and diagnostics for the default WordPress mail transport.
- Added the reports dashboard with delivery statistics, provider breakdowns and donut chart summaries.
- Added weekly and monthly HTML report emails based on aggregated log data.
- Added the multilingual administration foundation with German, English, French and Spanish admin language switching.
- Existing Classic SMTP, Hosting Relay and Microsoft 365 OAuth2 settings remain preserved when switching providers.
- Gmail OAuth2 remains visible as in development and is not selectable in this release.
1.1.0
- Added provider selection for classic SMTP, hosting relay and Microsoft 365 OAuth2.
- Added Microsoft 365 OAuth2 authorization, encrypted token storage, controlled token refresh and XOAUTH2 SMTP authentication.
- Added separated provider configurations so classic SMTP, hosting relay and Microsoft 365 can be switched without re-entering credentials.
- Extended diagnostics, redaction, privacy text and documentation for SMTP and Microsoft 365 OAuth2.
1.0.6
- Added WordPress.org plugin screenshots.
- Added screenshot descriptions to the plugin directory readme.
- No changes to SMTP transport or plugin functionality.
1.0.5
- Changed plugin licensing metadata to GPLv2 or later for WordPress.org submission.
- Added the official GPLv2 license file.
- Removed the Prostylemedia privacy policy link and brand-specific privacy text from test emails.
- Changed new-installation defaults to avoid subject storage, plugin-list export and theme export unless enabled by an administrator.
- Applied wp_unslash() before settings sanitization.
- Added WordPress privacy policy suggested text.
- Updated readme metadata and description for WordPress.org submission.
1.0.4
- SMTP test email redesigned.
- Prostylemedia logo integrated into the HTML test email.
- Dynamic WordPress site name kept in the footer.
- Footer extended with © 2026 Prostylemedia.
- Plain-text fallback extended.
- No changes to SMTP transport, logging or PHPMailer configuration.
1.0.3
- Unified vertical spacing between checkbox cards and option fields.
- Spacing around notices in settings and system status corrected.
- Responsive admin display visually unified.
- No changes to SMTP transport or mail log.
1.0.2
- Complete SMTP configuration on every phpmailer_init call, without object lock.
- Passive, fault-tolerant logging with at most 20 individual rows per request.
- Global log limit, verified full log clearing and compact diagnostics.
- Request ID and mail counter kept only in current request memory.
1.0.1
- Unique mail traces and ordered runtime events.
- Bounded, redacted runtime diagnostics with downloads.
- Idempotent PHPMailer configuration and emergency switch.
- Safe database migration while preserving existing data.
1.0.0
- Classic SMTP configuration with securely encrypted password.
- Test sending and understandable error diagnostics.
- Privacy-conscious mail log with management and CSV export.
- System status, conflict detection and redacted support export.
- Complete plugin-owned uninstall routine.