AuthenticSender replaces WordPress’ default mail() function with configurable SMTP, UseSend API, or Resend API delivery, giving you control over how your site sends email.

Delivery Method

Choose SMTP (default), UseSend API, or Resend API. Existing SMTP configurations keep working unchanged when SMTP is selected.

SMTP Configuration

Enable or disable SMTP routing with a single checkbox. When disabled (and no API delivery method is selected), WordPress falls back to its default mail() function. Configure your server connection with:

Host – your SMTP server hostname or IP address
Port – any valid port (1-65535), defaulting to 25
Encryption – None, TLS, or SSL
Authentication – optional username and password (stored encrypted with AES-256-GCM)

Provider Presets

Select a preset from the dropdown and the host, port, and encryption fields are filled in automatically. Supported providers:

Gmail
SendGrid
Mailgun
Postmark
Hostinger
UseSend (host smtp.usesend.com, username usesend, password = your API key)
Resend (host smtp.resend.com, username resend, password = your API key)

For a self-hosted UseSend SMTP proxy, use Custom and enter your proxy host with the same username/API-key password pattern.

UseSend API

Send mail through the UseSend HTTP API instead of SMTP:

Encrypted API key storage
Cloud hosting (app.usesend.com) or self-hosted instance URL
From, Reply-To, BCC, HTML/text, and attachments are mapped to the API

Resend API

Send mail through the Resend HTTP API instead of SMTP:

Encrypted API key storage
Direct delivery through api.resend.com
From, Reply-To, BCC, HTML/text, and attachments are mapped to the API

Sender Identity

Override the From name and From email address on outgoing emails when SMTP is enabled or an API delivery method is selected. Enable Force Identity to apply From, Reply-To, and BCC even when using WordPress default mail.

Additional Headers

Set global Reply-To (email and name) and BCC addresses. These apply when SMTP is enabled, an API delivery method is selected, or when Force Identity is on. The BCC field accepts multiple comma-separated addresses.

Password resets, email confirmations, and similar sensitive messages are never copied to BCC, so reset links and verification tokens are not shared with the BCC address.

Test Email

Send a test message directly from the settings page. AuthenticSender attempts delivery via wp_mail() and returns a clear success or error message, so a misconfiguration never leaves you guessing.

Email Log

Keep a database record of every email sent or failed. The log view includes:

Timestamp, recipient, subject, status, and delivery method (SMTP, UseSend, Resend, or WP Default)
Error message for failed deliveries
Filter by All / Success / Failed
Paginated table (20 entries per page)
One-click Clear Log with confirmation prompt
Configurable retention period (1-365 days); older entries are pruned automatically

Logging can be toggled on or off at any time from the Settings tab.

Security

SMTP passwords and API keys stored encrypted using AES-256-GCM with WordPress AUTH_KEY and SECURE_AUTH_KEY
Unique (non-default, non-identical) authentication keys are required before new SMTP passwords or API keys can be saved; English and localized sample phrases are detected
Self-hosted UseSend URLs must use HTTPS; localhost, private/reserved IPs, and unresolvable hosts are blocked by default; HTTP redirects are disabled
Global BCC skips password resets, email confirmations, and similar sensitive mail by default
Email log redacts subjects for the same sensitive-mail patterns
Plugin settings (including credentials) are not autoloaded on front-end requests