Integrate mailchimp in your wordpress with API with wpsubscribers
With WPSubscribers version 1.53 a API level support for Mailchimp has been implemented.
the old version was using a copy / paste of a form you were creating with Mailchimp access, it was causing some issues and may be kind of painful for some people.
Mailchimp API lets you have a fine control on your integration. Here is the step by step tutorial
1 ) Get or Create your API key from your mailchimp account


2 ) in WPSubscribers, go to “others settings” and put your API key

3 ) Get your List_id from Mailchimp
Connect to Mailchimp again, click on list and settings

from the list , you will the submenu Settings , then List Settings and Unique ID
you will have a special ID to copy like in this screenshot

3 ) you need to set up your form as usual
in Form Action URL: put exactly this value
/wp-content/plugins/wpsubscribers/mailchimp.php
If you use WordPress in multisite version use the complete url like http://youblogurl.com/wp-content/plugins/wpsubscribers/mailchimp.php
form name field is FNAME or anything else defined in mailchimp
default is FNAME, refer to the form code to adjust the field values
UPDATE ! depending on your host, you may name to use “email” and not “EMAIL” it’s lowercase sensitive

If you have anything, please contact us, or let a comment, and we will adjust it for you.
Important : ADD in hidden fields this line :
<input type="hidden" name="list_id" value="xxxxx">
where you replace xxxxx by your mailchimp list ID
Folks,
Step 3 is a little… terse. How exactly do you go about the task to “set up your form as usual… in… mailchimp.php”?
This implies that that step is documented somewhere, but I haven’t been able to find it. The comments in the mailchimp.php code file don’t help at all.
you are right, some part were incomplete. you shouldn’t hesitate to contact our support in such case.
What value should I put in the Email field when using API with MailChimp?
the tutorial has a missing part, it has been updated ( for the list_id ) also be careful the email / EMAIL for the form can be different ( case sensitive )
I got it to work using this tutorial…it’s in French, but it worked: http://www.youtube.com/watch?v=C7IB1NCg-G0