MailChimp API 3.0 and WordPress HTTP API

For MailChimp API connection I always used this function. So, if you need non-WordPress examples, please go there. But in this post I will show you more simpler way to connect MailChimp API via WordPress HTTP API functions – wp_remote_get() and wp_remote_post().

wp_remote_get()

You can use wp_remote_get() function for any API requests that requires GET method. That’s what I mean:

Get list subscribers count

In this example we will get all the information about a specific list in MailChimp and list subscribers count accordingly.

Read where to get your API key and a list ID.


$api_key = 'YOUR API KEY';
$list_id = 'YOUR LIST ID';
$dc = substr($api_key,strpos($api_key,'-')+1); // datacenter, it is the part of your api key - us5, us8 etc
$args = array(
 	'headers' => array(
		'Authorization' => 'Basic ' . base64_encode( 'user:'. $api_key )
	)
);

$response = wp_remote_get( 'https://'.$dc.'.api.mailchimp.com/3.0/lists/'.$list_id, $args );

$body = json_decode( $response['body'] );

if ( $response['response']['code'] == 200 ) {
	echo $body->stats->member_count;
} else {
	echo '' . $response['response']['code'] . $body->title . ': ' . $body->detail;
}

Get all subscribers emails from a list

In this table you can see some another WordPress HTTP API functions and their equivalents. You can use them or not – as you want.

Direct usage	WordPress function
`$response['response']['code']`	`wp_remote_retrieve_response_code( $response )`
`$response['body']`	`wp_remote_retrieve_body( $response )`
`$response['response']['message']`	`wp_remote_retrieve_response_message( $response )`


$api_key = 'YOUR API KEY';
$list_id = 'YOUR LIST ID';
$dc = substr($api_key,strpos($api_key,'-')+1); // us5, us8 etc
$args = array(
 	'headers' => array(
		'Authorization' => 'Basic ' . base64_encode( 'user:'. $api_key )
	)
);
$response = wp_remote_get( 'https://'.$dc.'.api.mailchimp.com/3.0/lists/'.$list_id.'/members/', $args );
$body = json_decode( wp_remote_retrieve_body( $response ) );
$emails = array();

if ( wp_remote_retrieve_response_code( $response ) == 200 ) {
	foreach ( $body->members as $member ) {
		if( $member->status != 'subscribed' )
			continue;
		$emails[] = $member->email_address;
	}
	print_r( $emails );
} else {
	echo '' . wp_remote_retrieve_response_code( $response ) . wp_remote_retrieve_response_message( $response ) . ': ' . $body->detail;
}

wp_remote_post()

Function wp_remote_post() can be used for POST, PUT, PATCH and DELETE API calls. Some examples are on the screenshot:

If I forgot about something, please let me know in comments.

Subscribe or unsubscribe user

The very popular function – let’s look how to implement it easily using wp_remote_post().


$api_key = 'YOUR API KEY';
$email = 'USER EMAIL';
$status = 'unsubscribed'; // subscribed, cleaned, pending

$args = array(
	'method' => 'PUT',
 	'headers' => array(
		'Authorization' => 'Basic ' . base64_encode( 'user:'. $api_key )
	),
	'body' => json_encode(array(
    		'email_address' => $email,
		'status'        => $status
	))
);
$response = wp_remote_post( 'https://' . substr($api_key,strpos($api_key,'-')+1) . '.api.mailchimp.com/3.0/lists/' . $list_id . '/members/' . md5(strtolower($email)), $args );

$body = json_decode( $response['body'] );
 
if ( $response['response']['code'] == 200 && $body->status == $status ) {
	echo 'The user has been successfully ' . $status . '.';
} else {
	echo '' . $response['response']['code'] . $body->title . ': ' . $body->detail;
}

Delete list members

If you want just to set status unsubscribed or cleaned for you subscriber – look at the previous example. But if you want to completely remove user email from a list, this code is for you then:


$api_key = 'YOUR API KEY';
$list_id = 'YOUR LIST ID';
$email = 'USER EMAIL';

$args = array(
	'method' => 'DELETE',
 	'headers' => array(
		'Authorization' => 'Basic ' . base64_encode( 'user:'. $api_key )
	)
);

wp_remote_post( 'https://' . substr($api_key,strpos($api_key,'-')+1) . '.api.mailchimp.com/3.0/lists/' . $list_id . '/members/' . md5(strtolower($email)), $args );

Batch subscribe all users with a specific role

There are not much examples of MailChimp batch operations over the web, but your can find another one on this website here.


$api_key = 'YOUR API KEY SHOULD BE HERE';
$list_id = 'YOUR LIST ID';
$dc = substr($api_key,strpos($api_key,'-')+1);
	
 
// "Schema describes object"? Not a problem
$body_args = new stdClass();
// all the batch operations will be stored in this array
$body_args->operations = array();
 
$wordpress_users_all = get_users( 'role=subscriber' ); // you may add another parameters into this function

// loop all found WP users

foreach ( $wordpress_users_all as $user ) {
	// a single batch operation object for each user
	$batch =  new stdClass();
	$batch->method = 'PUT';
	$batch->path = 'lists/' . $list_id . '/members/' . md5(strtolower($user->user_email));
	$batch->body = json_encode( array(
		'email_address' => $user->user_email,
		'status'        => 'subscribed',
		'merge_fields'  => array( 
			'FNAME' => $user->first_name,
			'LNAME' => $user->last_name
		)
	) );
	$body_args->operations[] = $batch;
}
 
$args = array(
	'method' => 'POST',
 	'headers' => array(
		'Authorization' => 'Basic ' . base64_encode( 'user:'. $api_key )
	),
	'body' => json_encode( $body_args )
);

$response = wp_remote_post( 'https://'.$dc.'.api.mailchimp.com/3.0/batches', $args );

$body = json_decode( wp_remote_retrieve_body( $response ) );
echo $body->id;

$body->id is the batch operation ID, try to get the status of a batch operation by yourself using wp_remote_get() and this API endpoint /batches/{batch_id}.

If you need more functionality, try to use my plugin, it allows to synchronize your WordPress users with MailChimp lists.
Download WordPress plugin

#MailChimp, #WordPress, #httpapi

Misha Rudrastyh

Hey guys and welcome to my website. For more than 10 years I've been doing my best to share with you some superb WordPress guides and tips for free.

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Comments — 5

Ripul 14 Jul 2016

I was just wondering when WordPress supports HTTP API MailChimp API can be implemented using it.
Thanks for sharing this.

Tom

4 Jun 2018

Again, your code save me!
However I tried to send order details according to Mailchimp API adapting your code in this way:

$api_key = xxx;
$list_id = xxx;

$order = array(
'headers' => array('Authorization' => 'Basic ' . base64_encode( 'user:'. $api_key )),
'body' => json_encode(array(
	'id' => 'order_453645',
	'customer' => array(
		'id' => 'user_307' ),
	'currency_code' => 'EUR',
	'order_total' => 99,
	'lines' => array(
		'id' => 'line_989',
		'product_id' => 'product_93',
		'product_variant_id' => 'product_4014',
		'quantity' => 1,
		'price' => 99)
	))
);
		
$response = wp_remote_post( 'https://us18.api.mailchimp.com/3.0/ecommerce/stores/. $list_id ./orders', $order );
$body = json_decode( $response['body'] );

But it doesn’t work.. I successfully add members, customers, stores and lists to Mailchimp but there’s no chance to send order details. Do you see something wrong in this code?
Thanks!

Misha

5 Jun 2018

Hey Tom,

First, $list_id variable is your store_id, right?
Second, you forgot the quotes:

$response = wp_remote_post( 'https://us18.api.mailchimp.com/3.0/ecommerce/stores/' . $list_id . '/orders', $order );

Third, where is 'method'=>'POST' parameter?

Try to print_r( $response ) and check out what is inside it.

Thanks for your reply Misha,
sorry for the typo: $list_id is my $store_id
I added the method POST parameter.
Customer id “user_307” is an existing user and product_id / product_variant_id is an existing product (I checked with a GET request), as well as store and list: created and working on Mailchimp. Priting the response produce this output: https://paste.ofcode.org/nq6NpndTCgbcnWEDKQjwMA

With this code I successfully create new customers, add members and create store but no luck with orders (update code):

$api_key = xxx;

$order = array(
'method' => 'POST',
'headers' => array('Authorization' => 'Basic ' . base64_encode( 'user:'. $api_key )),

'body' => json_encode(array(

	'id' => 'order_453645',
	'customer' => array(
		'id' => 'user_307' ),
	'currency_code' => 'EUR',
	'order_total' => 99,
	
	'lines' => array(
		'id' => 'line_989',
		'product_id' => 'product_93',
		'product_title' => 'Product 1',
		'product_variant_id' => 'product_4014',
		'product_variant_title' => 'medium',
		'quantity' => 1,
		'price' => 99
	)
	
	))
);
$response = wp_remote_post( 'https://us18.api.mailchimp.com/3.0/ecommerce/stores/stxxxx_1/orders/', $order );
$body = json_decode( $response['body'] );
}

Misha 7 Jun 2018

Hi Tom,

customer must be object, not array.

Comments are closed.