Lightweight module for ProcessWire that let you subscribe a user to a mailchimp list.

I have only tested it with PHP7.x and Processwire 3.x.

// Easily subscribe a user with SubscribeToMailchimp
$mc = $modules->get("SubscribeToMailchimp");
$mc->subscribe('[email protected]');

1. Download the zip file at Github or clone directly the repo into your site/modules
2. If you downloaded the zip file, extract it in your sites/modules directory.
3. You might have to change the folders name to 'SubscribeToMailchimp'.
4. Goto the modules admin page, click on refresh and install it.

1. Log into your Mailchimp account and go to Profile > Extras > API Keys.
2. If you don't have an API Key, create a new one.
3. Copy your API Key and paste it in the module settings (Processwire > Modules > Site > SubscribeToMailchimp).
4. Back in Mailchimp, go to the Audience, where you want your new subscribers.
5. Go to Settings > audience name and defaults. Copy the Audience ID and paste it into the module settings.
6. Test your settings with the provided checkbox.

// load module into template
$mc = $modules->get("SubscribeToMailchimp");

 // subscribe / update a user in your default audience
$mc->subscribe('[email protected]');

// add merge_fields to fill out user data, based on your audience MERGE_FIELD options
// You need to setup the fields at "Settings > List fields and *|MERGE|* tags" first!
$mc->subscribe('[email protected]', ['FNAME' => 'John', 'LNAME' => 'Doe']);

// Subscribe a user to a custom audience (other than default)
$mc->subscribe('[email protected]', ['FNAME' => 'John', 'LNAME' => 'Doe'], 'adcdef12345');

// Work with additional parameters (not merge_field values!)
$mc->subscribe('[email protected]', NULL, NULL, [
	'language' => 'en', // find language audience here: https://kb.mailchimp.com/lists/manage-contacts/view-and-edit-contact-languages#Language-Codes
	'vip' => true, // boolean vip status
	'location' => [ // geo location based on lat/log coordinates 
		'latitude' => '48.8722344',
		'longitude', => '2.7736192'
	],
	'interests' => [ // subscribe user to interest categories / groups based on group id
		'32fec3561e' => true, 
		'63mel4395m' => false
	]
]);

Additional methods

// Unsubscribe a user
$mc->unsubscribe('[email protected]'); 

// Unsubscribe a user from a custom audience
$mc->unsubscribe('[email protected]', 'abcdef1356');

// Permanently delete a user. Carefully, this step cannot be undone!
$mc->delete('[email protected]');

// Get the subscription status of a user.
$mc->getStatus('[email protected]');

// Static function to test your settings.
// If no audience id is provided, it will test your default audience and returns a formated html result
$mc->testSettings('audience id');

• This module does not do any data validation. Use a sever-sided validation like Valitron
• Make sure that you have set up your fields in your Mailchimp audience. You can do it at Settings > Audience fields and *|MERGE|* tags

Example usage after a form is submitted on your page:

// ... validation of form data

$mc = $modules->get("SubscribeToMailchimp");
$email = $input->post->email;
$subscriber = [
  'FNAME' => $input->post->firstname,
  'LNAME' => $input->post->lastname,
];
$mc->subscribe($email, $subscriber);

In case of trouble check your ProcessWire warning logs.

If you have enabled double opt-in (it is enabled by default) you will not see the subscriber, until he confirmed the subscription in the email sent by Mailchimp

• Check if you have the right audience ID and API Key.
• Check if you pass fields, that exist in your audience.
• Check if you pass a valid email address.

Go to Mailchimps Error Glossary for more Information

Until now, you can update from every version without changing your code

• #8: Fixed a bug, that prevents re-subscribing, if double-top in was disabled – thanks to @jliebermann for pointing this out
• #7: Removed the 'warning', that was logged appeared when trying to add a new subscriber – thanks to @horst-n for mentioning
• Updated wording from 'list' to 'audience' (Introducing Audience)

• #6: Fixed a bug, where you couldn't use the 'ADDRESS' merge field and removed more unused lines - Big thanks to @ml-eds for the quick fix!
• #4: Deleted unused line

• #3: Updated subscribe method. You can now add additional parameters like language or interests. Find more about this in the Mailchimp API Documentation

• #2: Added getStatus method $mc->getStatus($email, $list = "")

• #2: Added ability to resubscribe a user, if he has unsubscribed. The user will have to confirm his subscription again via double-opt-in (if not disabled)

• #1: Added testSetting method and a beautiful way to test your settings right in the module settings pages - Big thanks to @horst-n

• Centralized the validation warning via a constant

• Updated the getApiBase to be more flexible with different API calls

• Added 'Unsubscribe' method $mc->unsubscribe($email, $list = "")
• Added 'Delete' method $mc->delete($email, $list = "")
• Removed type declarations to be compatible with PHP 5.1* (thanks to wbmnfktr)
• Changed the way, the base url for the api gets called

*I have only tested it with PHP 7.x so far, so use on owners risk :)

Any suggestions? Join the Discussion in the ProcessWire Forums or contribute directly on Github.