Aaron D. Campbell

This plugins gives you a great framework to use for integrating with MailChimp.
Requires PHP5.

MailChimp Framework

MailChimp integration framework and admin interface as well as WebHook listener.  Requires PHP5.

Evan Herman

Tracy Levesque

Code Parrots

yikesitskevin

karmadharma

Jeremy Pry

Freddie

Easy Forms for Mailchimp allows you to add unlimited Mailchimp sign up forms to your WordPress site. You can add forms to posts, pages, sidebars and other widgetized areas. Your Mailchimp API Key connects your site to your account and pulls in all of your list information. List statistics can be viewed right from your dashboard.
<blockquote>
Note: For assistance with GDPR compliance, use our free add-on <a href="https://wordpress.org/plugins/eu-opt-in-compliance-for-mailchimp/" rel="ugc">GDPR Compliance for Mailchimp</a>.
</blockquote>
You can also extend the plugin’s functionality with our <a href="https://codeparrots.com/?utm_source=wp_plugin_repo&utm_medium=link&utm_campaign=easy_forms_for_mailchimp" rel="nofollow ugc">free and paid add-ons</a>.
Add a form to a site in a minute and a half
<iframe loading="lazy" class="youtube-player" width="750" height="422" src="https://www.youtube.com/embed/NRZbW-Da1XA?version=3&rel=1&showsearch=0&showinfo=1&iv_load_policy=1&fs=1&hl=en-US&autohide=2&wmode=transparent" allowfullscreen="true" style="border:0;" sandbox="allow-scripts allow-same-origin allow-popups allow-presentation allow-popups-to-escape-sandbox"></iframe>
Features
<ul>
<li>Build unlimited forms for any of your lists with an easy-to-use admin, including multiple forms for the same list.</li>
<li>Connect your website to your Mailchimp account with an API key.</li>
<li>Add forms to any post or page with our editor button or a shortcode.</li>
<li>Duplicate forms with a click.</li>
<li>Customize the form submission button text.</li>
<li>Display forms with inline fields.</li>
<li>Add forms to widgetized areas with our widget.</li>
<li>Allow users to sign up for interest groups, or pre-check groups in a hidden field.</li>
<li>Use our built-in CSS classes or add your own additional classes to form fields to style and customize forms.</li>
<li>Use a shortcode to display the number of subscribers on a given list.</li>
<li>Fully customize the success and error messages displayed back to the user.</li>
<li>Quickly toggle between single or double opt-in.</li>
<li>Disable or Enable the default welcome email.</li>
<li>Remove subscribers from your list through our admin interface.</li>
<li>Allow existing subscribers to update their profile information.</li>
<li>Redirect users to another post or page after form submission.</li>
<li>Enable Google reCAPTCHA protection on your forms.</li>
<li>Schedule form visibility by date/time.</li>
<li>Limit opt-ins by logged in users.</li>
<li>Use localized data/time pickers</li>
<li>Toggle on/off AJAX functionality on a per form basis.</li>
<li>Import/Export all forms and associated settings for use on other sites with the plugin installed.</li>
<li>Integrate with core WordPress forms: comments and registration.</li>
<li>Integrate with many popular third party plugins: WooCommerce, Easy Digital Downloads, BuddyPress, BbPress, Contact Form 7.</li>
<li>View your account activity like subscribes and unsubscribes.</li>
<li>View your list statistics and manage users and list settings.</li>
<li>Use advanced debugging to log errors as they occur, for easy troubleshooting.</li>
<li>Developer friendly! Use our many hooks and filters to extend the plugin.</li>
<li>Add-ons available to extend the core functionality of the plugin. <a href="https://codeparrots.com/?utm_source=wp_plugin_repo&utm_medium=link&utm_campaign=easy_forms_for_mailchimp" rel="nofollow ugc">Check them out</a>!</li>
</ul>
Integrations
Add Mailchimp opt-in checkboxes to the forms generated by these popular plugins.
<ul>
<li>WooCommerce</li>
<li>Easy Digital Downloads</li>
<li>BuddyPress</li>
<li>BbPress</li>
<li>Contact Form 7</li>
</ul>
Instructions on how to use the plugin can be <a href="https://codeparrots.com/support/knowledge-base/?utm_source=wp_plugin_repo&utm_medium=link&utm_campaign=easy_forms_for_mailchimp" rel="nofollow ugc">found in our Knowledge Base</a>.
If you experience any problems, please submit a New Issue on our <a href="https://github.com/evanherman/yikes-inc-easy-mailchimp-extender/issues" rel="nofollow ugc">Github Issue Tracker</a>. We respond to issues regarding the free plugin within a week. For expedited help, <a href="https://codeparrots.com/?utm_source=wp_plugin_repo&utm_medium=link&utm_campaign=easy_forms_for_mailchimp" rel="nofollow ugc">purchase one of our paid add-ons</a>.

Check out some of our <a href="https://codeparrots.com/?utm_source=wp_plugin_repo&utm_medium=link&utm_campaign=easy_forms_for_mailchimp" rel="nofollow ugc">other plugins</a>. 
Alongside the default functionality of the plugin we’ve included a number of hooks and filters to allow for a higher level of customization of your forms.
For information and code examples on how to implement the hooks and filters provided by our plugin, please see our <a href="https://codeparrots.com/support/knowledge-base/product/developer-documentation/?utm_source=wp_plugin_repo&utm_medium=link&utm_campaign=easy_forms_for_mailchimp" rel="nofollow ugc">Developer Documentation in the Knowledge Base</a>.

Easy Forms for Mailchimp

The ultimate Mailchimp WordPress plugin. Easily build unlimited forms for your Mailchimp lists, add them to your site and track subscriber activity.

MailChimp Framework vs Easy Forms for Mailchimp