Newsletters: Spam – Subscribe Form
In order to prevent spam subscriptions through the subscribe form in the WordPress Newsletter plugin you can make use of the CAPTCHA feature built into the plugin. Follow these easy steps:
You can choose between really simple captcha and google reCAPTCHA. You need to choose your Captcha type and set settings under Newsletters> Configuration> System- Captcha settings. View this documentation on more information on how to configure Captcha.
Configure the Subscribe Form
When using a sidebar widget subscribe form, you can simply drag a widget to your sidebar and for the ‘Use Captcha for Form‘ setting choose ‘Yes‘.
For the post/page embedded subscribe form (using the shortcode) or the hardcoded form, you can turn on the captcha image as a global setting under Newsletters > Configuration > Default Subscription Form settings.
Resulting Captcha in Subscribe Form
As a result, the subscribe form will show a captcha security image with a unique code in it each time which needs to be matched by the subscribing user in order to complete the subscription.