SWPMail - WordPress SMTP & Subscription Plugin

🇬🇧 English · 🇹🇷 Türkçe · 🇩🇪 Deutsch · 🇪🇸 Español · 🇫🇷 Français · 🇮🇹 Italiano · 🇯🇵 日本語 · 🇳🇱 Nederlands · 🇧🇷 Português

SWPMail is a fully customizable email subscription, notification, and sending infrastructure plugin that integrates with WordPress sites, supports 18 professional mail services, applies the configured SMTP/API setting to all WordPress emails sent via wp_mail(), and features enterprise-grade capabilities such as smart routing, failover, OAuth 2.0, email tracking & analytics, alarm system, DNS verification, and multilingual support (9 languages).

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Table of Contents

• Features
• Tech Stack
• System Requirements
• Installation
• Quick Start (Setup Wizard)
• Supported Mail Services (18 Providers)
• wp_mail Override System
• Smart Routing
• Connection Management & Failover
• OAuth 2.0 Integration
• Subscription System
• Shortcode Usage
• HTML Email Templates
• Trigger System
• Queue & Cron System
• Email Tracking & Analytics
• Alarm System
• DNS Checker (SPF / DKIM / DMARC)
• REST API
• WP-CLI Commands
• Admin Panel
• Security
• GDPR & Legal Compliance
• Multilingual Support (i18n)
• Theme Developer Guide
• Hooks Reference (Developer API)
• File Structure
• Database Design
• Diagnostics & Repair Tools
• Testing
• FAQ (Frequently Asked Questions)
• License

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Tech Stack

Layer	Technology	Details
Backend	PHP 7.4+	24,000+ lines — OOP with Factory, Strategy & Template Method patterns
Frontend	JavaScript (jQuery)	1,900+ lines — AJAX-driven admin UI, multi-step setup wizard
Styling	CSS3 (Custom Properties)	4,000+ lines — 570+ CSS variables, "Parchment & Forest" design system
Typography	Google Fonts	Cormorant Garamond (display), Nunito (body), JetBrains Mono (code)
Editor	CodeMirror	Built-in HTML template editor via WordPress code editor API
Database	MySQL / MariaDB	4 custom InnoDB tables with optimized indexes
CLI	WP-CLI	16 subcommands for full terminal management
API	WordPress REST API	3 endpoints + 32 AJAX handlers
Testing	PHPUnit 9 + Brain\Monkey	WordPress-aware unit testing
Linting	PHPCS + WPCS	WordPress Coding Standards enforced
i18n	WordPress L10n	9 languages with .po / .mo files
Dependencies	None (runtime)	Zero external libraries — pure WordPress HTTP API

At a Glance

📦 30,000+ lines of code    🗂️ 67 PHP classes       🎨 570+ CSS variables
📮 18 mail providers         🔌 48 extensibility hooks  🗄️ 4 custom DB tables
🌍 9 languages              ⚡ 16 WP-CLI commands      📡 3 REST + 32 AJAX endpoints
🔔 5 alarm channels          📋 10 email templates      🔄 6 cron events

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Features

Sending Infrastructure

• 18 Mail Service Providers: PHP Mail, Generic SMTP, SendLayer, SMTP.com, Gmail, Outlook, Mailgun, SendGrid, Postmark, Brevo, Amazon SES, Resend, Elastic Email, Mailjet, MailerSend, SMTP2GO, SparkPost, Zoho Mail
• Global wp_mail Override: All WordPress emails (WooCommerce, Contact Form 7, password reset, etc.) are sent through the selected provider
• Smart Routing: Rule-based conditional email routing — different providers can be used based on criteria such as recipient, subject, source
• Failover & Health Check: Automatic fallback to backup provider when the primary provider fails, with health check mechanism
• OAuth 2.0: Full OAuth 2.0 flow for Gmail and Outlook, with automatic token refresh

Subscription & Notification

• Subscription System: Instant, daily digest, and weekly digest options
• Double Opt-in: Double confirmation mechanism enabled by default
• 5 Built-in Triggers: New post, new user, user login, new comment, password reset
• Extensible Trigger System: Custom trigger support for third-party plugins
• Queue System: WP-Cron based asynchronous email queue with retry mechanism

Templates & Content

• HTML Mail Templates: Fully customizable responsive email templates with theme override support
• Template Editor: CodeMirror-based HTML template editing in the admin panel
• Variable System: Dynamic variables like {{post_title}}, {{site_name}} in templates

Monitoring & Analytics

• Email Tracking: Open (open pixel) and click (click redirect) tracking
• Analytics Dashboard: Total/unique opens, total/unique clicks, rate calculations
• Alarm System: Instant error notifications via Slack, Discord, Microsoft Teams, Twilio SMS, and custom webhooks
• DNS Checker: Automatic verification of SPF, DKIM, DMARC records

Developer & Management

• REST API: Programmatic subscriber management
• WP-CLI: Full management via terminal with 16+ commands
• Setup Wizard: Step-by-step configuration on first activation
• Conflict Detector: Detection of 18+ known conflicting plugins
• Database Repair: Table/column/index deficiency diagnostics and automatic repair
• Email Logs: Detailed sending records and filtering

Security & Compliance

• AES-256-CBC Encryption: API keys are stored encrypted in the database with HMAC-SHA256 verification
• Rate Limiting: IP-based request limiting and bot protection (honeypot)
• GDPR Compliant: WordPress Privacy API integration, unsubscribe links
• Multilingual (9 Languages): English, Türkçe, Deutsch, Español, Français, Italiano, 日本語, Nederlands, Português (BR)
• Zero External Dependencies: No external libraries required; uses WordPress HTTP API

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System Requirements

Requirement	Minimum	Recommended
PHP	7.4	8.1+
WordPress	6.0	6.7+
MySQL	5.7	8.0+
MariaDB	10.3	10.6+
cURL	Enabled	Enabled
OpenSSL	Enabled	Enabled

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Installation

Via WordPress Admin Panel

1. Go to Plugins > Add New
2. Upload the swpmail folder as a ZIP file
3. Click the Activate button

Manual Installation

1. Upload the swpmail folder to the /wp-content/plugins/ directory:

   # Extract the zip file
   unzip swpmail.zip -d /path/to/wp-content/plugins/

2. Activate it from the Plugins page in the WordPress admin panel

After Activation

When the plugin is activated, it automatically:

• Creates 4 database tables (swpm_subscribers, swpm_queue, swpm_logs, swpm_tracking)
• Saves default settings
• Schedules WP-Cron tasks (6 tasks)
• Sets up the setup wizard redirect (swpm_activation_redirect transient)

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Quick Start (Setup Wizard)

When the plugin is activated for the first time, the Setup Wizard opens automatically and guides you through the configuration process step by step.

Wizard Steps

1. Provider Selection — Choose your mail provider from 18 providers
2. Credentials — Enter API key or SMTP credentials
3. Test Send — Send a test email to verify the connection
4. Complete — swpm_setup_complete is marked, and you are redirected to the dashboard

Manual Configuration

If you skipped the wizard or want to change settings later:

1. Go to the SWPMail > Mail Settings page
2. Select your mail service provider (e.g., SMTP, Mailgun, SendGrid)
3. Enter the required information (API key, host, port, etc.)
4. Click the Send Test Email button to verify the connection
5. Add the [swpmail_subscribe] shortcode to any page on your site
6. Choose which events will send emails from the SWPMail > Triggers page

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Supported Mail Services (18 Providers)

SMTP-Based Providers

#	Service	Method	Description
1	PHP Mail	PHP mail()	Server default, no configuration required
2	Generic SMTP	PHPMailer / SMTP	Any SMTP server
3	Gmail	SMTP / OAuth 2.0	Google account, App Password or OAuth
4	Outlook	SMTP / OAuth 2.0	Microsoft 365 / Outlook.com
5	Zoho Mail	SMTP	Zoho Mail account

HTTP API-Based Providers

#	Service	Method	Free Quota
6	Mailgun	HTTP API	100/day
7	SendGrid	HTTP API	100/day (trial only)
8	Postmark	HTTP API	100/month (test)
9	Brevo (Sendinblue)	HTTP API	300/day
10	Amazon SES	HTTP API (SDK-less)	3,000/month
11	Resend	HTTP API	3,000/month
12	Elastic Email	HTTP API	100/day
13	Mailjet	HTTP API	200/day
14	MailerSend	HTTP API	3,000/month
15	SendLayer	HTTP API	Paid only
16	SMTP.com	HTTP API	Paid only
17	SMTP2GO	HTTP API	1,000/month
18	SparkPost	HTTP API	500/month (test)

Provider Configuration

Required information for each provider:

• PHP Mail: No configuration required (server default)
• Generic SMTP: Host, Port, Username, Password, Encryption (TLS/SSL/None)
• Gmail: Email, App Password or OAuth 2.0 (Client ID + Secret)
• Outlook: Email, Password or OAuth 2.0 (Client ID + Secret + Tenant)
• Zoho Mail: Email, App Password
• Mailgun: API Key, Domain, Region (US/EU)
• SendGrid: API Key
• Postmark: Server Token, Message Stream
• Brevo: API Key
• Amazon SES: Access Key, Secret Key, Region
• Resend: API Key
• Elastic Email: API Key
• Mailjet: API Key, Secret Key
• MailerSend: API Token
• SendLayer: API Key
• SMTP.com: API Key, Sender ID
• SMTP2GO: API Key
• SparkPost: API Key
• Zoho Mail: Email, App Password

Note: All API keys and passwords are encrypted with AES-256-CBC + HMAC-SHA256 and stored in the database. WordPress salt keys are used as the encryption key.

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wp_mail Override System

When the plugin is active and a provider is configured, all wp_mail() calls in the system are automatically sent through the selected provider.

How It Works

• SMTP Providers: PHPMailer is configured via the phpmailer_init hook
• API Providers: Sending is fully taken over via the pre_wp_mail filter

From Address Priority Order

1. From Email / Name in SWPMail settings   (highest priority)
2. wp_mail_from / wp_mail_from_name filters
3. WordPress default (wordpress@domain.com)

Disabling the Override

// Skip the override for a specific wp_mail call
add_filter( 'swpm_skip_override', '__return_true' );
wp_mail( $to, $subject, $body );
remove_filter( 'swpm_skip_override', '__return_true' );

Or disable the SWPMail > Settings > Override wp_mail option from the admin panel.

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Smart Routing

SWPMail allows you to send different emails through different providers using the conditional email routing engine.

Rule Structure

Each routing rule consists of the following components:

Component	Description
Name	Descriptive name for the rule
Priority	Lower number = evaluated first
Provider	Which provider to use for emails matching this rule
Conditions	Matching criteria (AND logic)

Condition Fields

Field	Description
to	Recipient email address
subject	Email subject
from	Sender address
header	Any header value
source	Source that triggered the email (plugin, etc.)

Condition Operators

contains, not_contains, equals, not_equals, starts_with, ends_with, matches (regex)

Example Scenarios

Rule: "WooCommerce Orders via Postmark"
  Condition: subject contains "Order"
  Provider: postmark
  Priority: 10

Rule: "Bulk Mail via SendGrid"
  Condition: source equals "swpmail_trigger"
  Provider: sendgrid
  Priority: 20

Emails that don't match any rule are sent through the default (primary) provider.

Rules are stored in JSON format in the swpm_routing_rules option and managed from the SWPMail > Smart Routing page.

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Connection Management & Failover

SWPMail provides an automatic failover mechanism to prevent service interruptions when the primary provider goes down.

How It Works

Email Sending
     ↓
Primary Provider → Successful? → Sent ✓
     ↓ (Failed)
Failure Counter +1
     ↓
Threshold Exceeded? (3 consecutive errors)
  YES → Switch to Backup Provider → Send
  NO  → Retry
     ↓
Health Check after 5 minutes → Return to primary if healthy

Features

• Automatic Failover: Backup provider activates after 3 consecutive failures
• Health Check: Primary provider status monitored via lightweight test sends
• Cooldown Period: Health checks performed at 5-minute intervals
• AJAX Status: swpm_health_check, swpm_get_connection_status endpoints

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OAuth 2.0 Integration

OAuth 2.0 authorization flow is supported for Gmail and Outlook providers.

Supported Services

Service	Auth Endpoint	Token Endpoint
Gmail	accounts.google.com/o/oauth2/v2/auth	oauth2.googleapis.com/token
Outlook	login.microsoftonline.com/common/oauth2/v2.0/auth	login.microsoftonline.com/common/oauth2/v2.0/token

OAuth Flow

1. Click the Authorize button in the admin panel
2. Sign in with your Google/Microsoft account and grant permissions
3. Token is received via the callback URL and stored encrypted
4. Automatic refresh when the token expires

AJAX Endpoints

• swpm_oauth_start — Start OAuth flow
• swpm_oauth_callback — Callback processing
• swpm_oauth_disconnect — Disconnect OAuth

Note: If OAuth is not configured, SMTP connection with App Password is used for Gmail and standard password for Outlook.

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Subscription System

Subscription Flow

Form Submission → AJAX (nonce + rate limit + honeypot + GDPR)
     ↓
Double Opt-in Enabled?
  YES → status: pending → Confirmation email → Token verification → confirmed
  NO  → status: confirmed → Welcome email
     ↓
Frequency: instant / daily / weekly

Subscription Statuses

Status	Description
pending	Awaiting confirmation (double opt-in)
confirmed	Active subscriber
unsubscribed	Unsubscribed
bounced	Email bounced

Subscription Frequencies

Frequency	Description
instant	Immediately (on every new post)
daily	Daily digest (configurable hour)
weekly	Weekly digest (configurable day)

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Shortcode Usage

Basic Usage

[swpmail_subscribe]

All Parameters

Parameter	Default	Description
title	From settings	Form title
show_name	false	Show name field
frequency	From settings	Show frequency selection (true/false)
frequency_default	instant	Default frequency
style	default	Form style (default/minimal)
button_text	"Subscribe"	Button text

Examples

<!-- With name field -->
[swpmail_subscribe show_name="true" title="Subscribe to Newsletter"]

<!-- With specific frequency -->
[swpmail_subscribe frequency_default="weekly" frequency="false"]

<!-- Minimal style -->
[swpmail_subscribe style="minimal" button_text="Join"]

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HTML Email Templates

Built-in Templates

Template ID	Usage	Variables
base	Base layout for all emails	{{content}}
confirm-subscription	Double opt-in email	{{confirm_url}}, {{subscriber_name}}
welcome	Welcome email	{{subscriber_name}}, {{site_name}}
new-post	New post notification	{{post_title}}, {{post_url}}, {{post_excerpt}}, {{post_thumbnail}}, {{author_name}}
new-user	New user registration notification	{{username}}, {{login_url}}
new-comment	New comment notification	{{commenter_name}}, {{comment_excerpt}}, {{post_title}}
user-login	User login notification	{{username}}, {{ip_address}}, {{login_time}}
password-reset	Password reset notification	{{username}}, {{reset_link}}
digest-daily	Daily digest	{{post_list}}, {{date}}
digest-weekly	Weekly digest	{{post_list}}, {{week_start}}, {{week_end}}

Global Variables (Available in All Templates)

Variable	Description
{{site_name}}	Site name
{{site_url}}	Site URL
{{site_logo}}	Site logo URL
{{year}}	Current year
{{from_name}}	Sender name
{{privacy_url}}	Privacy policy URL
{{unsubscribe_text}}	"Unsubscribe" text
{{visit_site_text}}	"Visit Site" text

Template Loading Priority

1. swpm_template_path filter          (highest)
2. Theme: /swpmail/templates/{id}.html
3. Database (saved via admin editor)
4. Plugin: /templates/default/{id}.html (lowest)

Theme Override

You can override templates in your theme folder:

your-theme/
└── swpmail/
    └── templates/
        ├── new-post.html
        └── welcome.html

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Trigger System

Built-in Triggers

Trigger	WordPress Hook	Template
New Post Published	transition_post_status	new-post
New User Registered	user_register	new-user
User Login	wp_login	user-login
New Comment	comment_post	new-comment
Password Reset	retrieve_password	password-reset

Creating Custom Triggers

Third-party plugins or theme developers can add their own triggers:

class My_Custom_Trigger extends SWPM_Trigger_Base {

    public function get_key():         string { return 'my_custom_event'; }
    public function get_label():       string { return 'My Custom Event'; }
    public function get_hook():        string { return 'my_plugin_event_fired'; }
    public function get_template_id(): string { return 'my-custom-template'; }

    public function get_subject( array $data ): string {
        return 'Custom event: ' . $data['title'];
    }

    public function get_recipients( array $data ): array {
        return swpm( 'subscriber' )->get_confirmed_by_frequency( 'instant' );
    }

    protected function prepare_data( ...$args ): array {
        return [
            'title'   => $args[0],
            'content' => $args[1] ?? '',
        ];
    }
}

// Register the trigger
add_action( 'swpm_register_triggers', function( SWPM_Trigger_Manager $manager ) {
    $manager->register( new My_Custom_Trigger() );
} );

Trigger Control Filters

// Conditionally stop a specific trigger
add_filter( 'swpm_trigger_should_send_new_post', function( $proceed, $data ) {
    // Skip posts published from draft (custom logic)
    if ( $data['post_id'] && get_post_meta( $data['post_id'], '_skip_notification', true ) ) {
        return false;
    }
    return $proceed;
}, 10, 2 );

// Extend triggerable post types
add_filter( 'swpm_trigger_new_post_types', function( $types ) {
    $types[] = 'product';  // Also trigger for WooCommerce products
    return $types;
} );

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Queue & Cron System

Queue Operation

• Emails are added to the swpm_queue table
• Processed by WP-Cron every 5 minutes
• Failed sends are retried with a maximum of 3 attempts
• Items stuck in "sending" status for more than 10 minutes are automatically reset

Scheduled Tasks

Task	Interval	Description
swpm_process_queue	5 min	Queue processing (batch: 50 items)
swpm_send_daily_digest	Daily	Daily digest sending (default: 09:00)
swpm_send_weekly_digest	Weekly	Weekly digest sending (default: Monday)
swpm_cleanup_logs	Daily	Clean up old log records
swpm_cleanup_queue	Daily	Clean up sent/failed queue items
swpm_cleanup_tracking	Daily	Clean up old tracking data

Configuration Options

• swpm_daily_send_hour — Hour for daily digest sending (default: 9)
• swpm_weekly_send_day — Day for weekly digest sending (default: monday)
• Cron tasks are automatically rescheduled when settings change

Queue Settings

// Customize batch size (for shared hosting)
add_filter( 'swpm_queue_batch_size', fn() => 10 );

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REST API

Namespace: swpmail/v1

Endpoints

Method	Endpoint	Auth	Description
POST	/swpmail/v1/subscribe	Public	Create new subscriber
GET	/swpmail/v1/subscribers	Admin	Subscriber list (paged)
DELETE	/swpmail/v1/subscribers/{id}	Admin	Delete subscriber

Usage Examples

New Subscriber:

curl -X POST https://site.com/wp-json/swpmail/v1/subscribe \
  -H "Content-Type: application/json" \
  -d '{"email": "example@email.com", "name": "Name", "frequency": "instant"}'

Subscriber List (Admin):

curl https://site.com/wp-json/swpmail/v1/subscribers \
  -H "X-WP-Nonce: {nonce}" \
  --cookie "wordpress_logged_in_xxx=..."

Response Formats

Successful Subscription (201):

{
  "message": "Subscription successful.",
  "id": 42
}

Error (422):

{
  "message": "This email is already subscribed."
}

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Email Tracking & Analytics

Email Tracking System

SWPMail automatically adds tracking mechanisms to sent HTML emails:

Feature	Method	Description
Open Tracking	1×1 invisible pixel	Sends request to swpm_open endpoint when email opened
Click Tracking	Link proxy redirect	Links are rewritten through swpm_click

• Tracking data is stored in the swpm_tracking table with hash, queue_id, IP, and user agent information
• Rewrite rules are registered in the init hook (priority 5)

Analytics Dashboard

Metrics displayed on the SWPMail > Dashboard page:

• Total Opens / Unique Opens counts
• Total Clicks / Unique Clicks counts
• Open Rate and Click Rate
• 30-day retrospective analysis (configurable)

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Alarm System

5 different alarm channels are supported to receive instant notifications when sending errors occur.

Alarm Channels

Channel	Key	Method	Configuration
Slack	slack	Webhook	Incoming Webhook URL
Discord	discord	Webhook	Discord Webhook URL
Microsoft Teams	teams	Webhook	Teams Incoming Webhook URL
Twilio SMS	twilio	REST API	Account SID, Auth Token, Phone
Custom	custom	HTTP POST	Target URL, Payload format

Triggering

• Notifications are sent to active alarm channels when the swpm_mail_failed hook fires
• Each channel is configured and can be tested from the SWPMail > Alarms page
• AJAX endpoint: swpm_test_alarm_channel

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DNS Checker (SPF / DKIM / DMARC)

Verifying domain DNS records is critical for improving email deliverability.

Verified Records

Record	Description
SPF	Specifies which servers can send mail on behalf of the domain
DKIM	Ensures the authenticity of the email signature
DMARC	Defines what to do when SPF/DKIM fails

Features

• Verification using the dns_get_record() PHP function
• Automatically runs when mail settings are saved
• 15-minute transient caching (swpm_dns_ + md5(domain))
• Analysis based on deliverability best practices
• Accessible from the SWPMail > DNS Checker page

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WP-CLI Commands

SWPMail offers comprehensive CLI commands under the wp swpmail namespace.

General Commands

# General status and health report
wp swpmail status

# Send test email
wp swpmail test --to=example@email.com

# Reset all plugin settings
wp swpmail reset --yes

Provider Management

# Active provider info
wp swpmail provider

# List available providers
wp swpmail provider list

# Switch provider
wp swpmail provider switch sendgrid

Queue Management

# List queue items
wp swpmail queue list --status=pending --limit=20

# Process queue
wp swpmail queue process --limit=50

# Flush sent/failed items
wp swpmail queue flush --status=sent --older-than="7 days"

Logs & Diagnostics

# Show recent log records
wp swpmail log --level=error --limit=50

# Database diagnostics
wp swpmail db diagnose

# Database repair (dry run)
wp swpmail db repair --dry-run

# Conflict detection
wp swpmail conflicts

Cron & Subscriber Management

# List scheduled cron events
wp swpmail cron list

# Manually trigger cron event
wp swpmail cron run swpm_process_queue

# List subscribers
wp swpmail subscriber list --status=confirmed --limit=100

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Admin Panel

Menu Structure

SWPMail (dashicon: email)
├── Dashboard        → Statistics, analytics, queue status, recent logs
├── Subscribers      → Subscriber management with WP_List_Table (search/filter/delete)
├── Email Templates  → CodeMirror-based HTML template editor
├── Triggers         → Enable/disable triggers, create custom triggers
├── Mail Settings    → 18 provider selection and configuration, test sending
├── DNS Checker      → SPF, DKIM, DMARC record verification
├── Smart Routing    → Rule-based conditional email routing
├── Email Logs       → Detailed sending records, filtering
├── Alarms           → Slack, Discord, Teams, Twilio, Custom alarm configuration
├── Settings         → General settings, GDPR, subscription, override settings
└── Tools            → Database repair, conflict detection, system info

Dashboard

• Total / confirmed / pending / unsubscribed subscriber counts
• Active provider info and failover status
• Queue status (pending/sent/failed)
• Open / Click analytics metrics
• Last cron execution time
• DNS verification status
• Last 10 log records

Subscriber Management

• Search: By email or name
• Filter: Status-based (pending, confirmed, unsubscribed, bounced)
• Sort: Email, status, registration date
• Bulk Action: Bulk delete selected subscribers
• Single Delete: Via row action

Template Editor

• CodeMirror HTML editor
• Available variables list
• Save / Reset (restore to default)
• AJAX-based saving

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Security

Topic	Method
CSRF	wp_create_nonce() + check_ajax_referer() / wp_verify_nonce()
XSS	esc_html(), esc_attr(), esc_url(), wp_kses_post()
SQL Injection	$wpdb->prepare() — in all queries
Direct File Access	if ( ! defined( 'ABSPATH' ) ) exit; in every PHP file
Permission Check	current_user_can( 'manage_options' ) in all admin operations
Rate Limiting	Transient API with 5 requests per IP / 10 minutes
Bot Protection	Hidden honeypot field (swpm_website)
Token Security	random_bytes(32) + bin2hex() (64 characters)
API Key Encryption	AES-256-CBC + HMAC-SHA256 + WordPress salt
IP Validation	FILTER_VALIDATE_IP (IPv4 + IPv6)
OAuth Token Storage	Encrypted token storage, automatic refresh
Conflict Detection	wp_mail override analysis via ReflectionFunction
Origin/Referer	Origin/referer validation in REST API

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GDPR & Legal Compliance

• Double Opt-in: Enabled by default
• Unsubscribe: Unsubscribe link in every email
• GDPR Consent Checkbox: Personal data collection consent (with privacy policy link)
• WordPress Privacy API: Data export and deletion integration
• IP Logging: IP address recorded for KVKK/GDPR compliance
• Log Cleanup: Logs older than 30 days are automatically cleaned up (configurable)
• Token Expiration: Confirmation tokens expire after 48 hours (configurable)

WordPress Privacy API

The plugin provides full integration with WordPress Privacy API:

• Data Export: Tools > Export Personal Data → Subscriber data is included
• Data Deletion: Tools > Erase Personal Data → Subscriber records are removed

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Multilingual Support (i18n)

• Text domain: swpmail
• Language files: languages/ folder
• Built-in languages (9):

Language	Locale
English	default
Türkçe	tr_TR
Deutsch	de_DE
Español	es_ES
Français	fr_FR
Italiano	it_IT
日本語	ja
Nederlands	nl_NL
Português (Brasil)	pt_BR

Adding Translations

1. Open the languages/swpmail.pot file with Poedit or a similar tool
2. Create your translations
3. Save the .po and .mo files to the languages/ folder
4. File name format: swpmail-{locale}.po (e.g., swpmail-de_DE.po)

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Theme Developer Guide

Shortcode Template Override

// Load subscribe-form.php template from theme folder
add_filter( 'swpm_subscribe_template', function( $path, $atts ) {
    $theme_path = get_stylesheet_directory() . '/swpmail/subscribe-form.php';
    return file_exists( $theme_path ) ? $theme_path : $path;
}, 10, 2 );

Email Template Override

Copy email templates as HTML files to the your-theme/swpmail/templates/ directory. Templates in this directory are loaded before the plugin's default templates.

Service Container Access

// Global helper function
$mailer      = swpm( 'mailer' );
$subscriber  = swpm( 'subscriber' );
$provider    = swpm( 'provider' );
$queue       = swpm( 'queue' );
$engine      = swpm( 'template_engine' );
$router      = swpm( 'router' );
$tracker     = swpm( 'tracker' );
$analytics   = swpm( 'analytics' );
$connections = swpm( 'connections_manager' );

// Or static access
$mailer = SWPMail::get( 'mailer' );

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Hooks Reference (Developer API)

Action Hooks

Hook	Parameters	Description
swpm_subscriber_created	$id, $email, $frequency	When a new subscriber is created
swpm_subscriber_confirmed	$id, $email	When a subscriber is confirmed
swpm_subscriber_unsubscribed	$id, $email	When a subscription is cancelled
swpm_register_triggers	$trigger_manager	Custom trigger registration point
swpm_mail_sent	$result, $recipient, $mail_data	When an email is sent successfully
swpm_mail_failed	$result, $recipient, $mail_data	When sending fails (triggers alarms)
swpm_auth_failure	$provider_key	API authentication failure
swpm_smtp_exception	$exception, $friendly_msg	When an SMTP error occurs

Filter Hooks

Hook	Returns	Description
swpm_provider_registry	array	Add new provider to the provider list
swpm_subscribe_template	string	Change shortcode form template path
swpm_template_path	string	Change email template path
swpm_trigger_should_send_{key}	bool	Stop/allow trigger sending
swpm_trigger_new_post_types	array	Extend triggerable post types
swpm_pre_send	bool	Pre-send filter
swpm_mail_headers	array	Modify mail headers
swpm_skip_override	bool	Skip wp_mail override
swpm_queue_batch_size	int	Queue batch size (default: 50)
swpm_api_timeout	int	HTTP request timeout (default: 20s)
swpm_confirm_token_expiry	int	Token expiry (default: 172800s / 48 hours)
swpm_blocked_email_domains	array	Blocked email domains
swpm_log_retention_days	int	Log retention period (default: 30 days)

Usage Examples

// 1. Add custom provider
add_filter( 'swpm_provider_registry', function( $registry ) {
    $registry['sparkpost'] = 'My_SparkPost_Provider';
    return $registry;
} );

// 2. Stop sending to specific recipient
add_filter( 'swpm_pre_send', function( $send, $recipient, $mail_data ) {
    if ( 'skip@example.com' === $recipient ) {
        return false;
    }
    return $send;
}, 10, 3 );

// 3. Increase API timeout
add_filter( 'swpm_api_timeout', fn() => 30 );

// 4. Add Reply-To header
add_filter( 'swpm_mail_headers', function( $headers ) {
    $headers[] = 'Reply-To: support@example.com';
    return $headers;
} );

// 5. Reduce token expiry to 24 hours
add_filter( 'swpm_confirm_token_expiry', fn() => DAY_IN_SECONDS );

// 6. Notify Slack about sending errors
add_action( 'swpm_mail_failed', function( $result, $recipient ) {
    wp_remote_post( SLACK_WEBHOOK_URL, [
        'body' => wp_json_encode( [
            'text' => "Mail failed: {$recipient} — " . $result->get_error_message(),
        ] ),
    ] );
}, 10, 2 );

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File Structure

swpmail/
├── swpmail.php                          ← Main file (header + bootstrap)
├── readme.txt                           ← WordPress.org readme
├── README.md                            ← Detailed project documentation
├── uninstall.php