Val Davis

RDS Newsletter is a straightforward email newsletter plugin that does not overcomplicate things.
Features: 
* Import subscribers via CSV or plain text (one email per line) 
* Paste raw HTML as your email content 
* Optional templates (Basic and Modern included) 
* Batch sending with configurable limits (default 500 per hour) 
* Subscriber groups for targeted sends 
* Double opt-in with confirmation emails 
* Open and click tracking with reports 
* Automatic unsubscribe links in every email 
* Bounce detection with auto-delete via IMAP 
* IP address and timestamp logging for compliance 
* Signup and unsubscribe shortcodes 
* Send test emails before sending to your list 
* Schedule newsletters for later 
* Duplicate newsletters 
* Export subscribers as CSV
<h3>Shortcodes</h3>
Signup form: 
 [rdsnl_signup]
Optional attributes: 
* <code>title="Subscribe to our newsletter"</code> 
* <code>button_text="Subscribe"</code> 
* <code>group="3"</code> (group ID to auto-assign)
Unsubscribe form: 
 [rdsnl_unsubscribe]

RDS Newsletter

A self-hosted email newsletter plugin for WordPress with subscriber management, batch sending, open and click tracking, and bounce processing.

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Mailster Newsletter Plugin

Integrates Mailster Newsletter Plugin with Gravity Forms to subscribe users with a Gravity Form. 
Requires the Mailster Newsletter plugin and the Gravity Forms plugin
<blockquote>
This Plugin requires <a href="https://mailster.co/?utm_campaign=wporg&utm_source=wordpress.org&utm_medium=readme&utm_term=Gravity+Forms" rel="nofollow ugc">Mailster Newsletter Plugin for WordPress</a>
</blockquote>

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RDS Newsletter vs Mailster Gravity Forms